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Secondary 2 · Mathematics
Algebra · Algebra

Monomials

Before you start, make sure you know: Monomials and operations with monomials (Secondary Year 1 (first cycle))
Before you start, make sure you know: Perimeters and areas of polygons (Secondary Year 1 (first cycle))

A game app on a cell phone earns its owner a profit for each download that is expressed by the monomial $7x^2y$. Before doing any calculations with it, you need to know how to read it: which part is the number and which part is the letters.

What a monomial is

Diagram of the monomial 7x²y that points out the coefficient 7, the literal part x²y, and the degree calculated as 2 plus 1 equals 3. 7 x²y coefficient literal part degree = 2 + 1 = 3 (y has exponent 1, even though it isn't written)

The relative degree with respect to a letter is the exponent of that letter. In $-5x^ay^b$, the relative degree with respect to $x$ is $a$ and with respect to $y$ is $b$; the absolute degree is $a + b$. For example, in $7x^2y$ the relative degree with respect to $x$ is $2$, with respect to $y$ is $1$, and the absolute degree is $3$.

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In an app store, the profit per game download is expressed by the monomial $7x^2y$. Identify the following elements of this expression: Coefficient: Literal part: Degree…

In an app store, the profit per game download is expressed by the monomial $7x^2y$. Identify the following elements of this expression:

  • Coefficient:

  • Literal part:

  • Degree of the monomial:

Solve
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In a math app, a bot has incorrectly classified some monomials. Your task is to correct the following table by identifying the coefficient, the literal part, and the…

In a math app, a bot has incorrectly classified some monomials. Your task is to correct the following table by identifying the coefficient, the literal part, and the degree of each one. If you find any error in the bot's classification, write it correctly:

Monomial Coefficient Literal part Degree
$-5x^2y$ $5$ $x^2y$ $2$
$\frac{3}{4}ab^3c$ $3$ $ab^3c$ $4$
$-x^4$ $-1$ $x$ $4$
$7$ $7$ None $1$
Solve

Like monomials

$5x^2$ and $-2x^2$ are like monomials. $5x^2$ and $5x$ are not, even though they look similar: the exponents don't match.

Comparison of like monomials, which share the same literal part, versus unlike monomials. like monomials 5x² −2x² same literalpart: x² unlike monomials (different literal part) 5x² 5x degree 2and degree 1
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We are organising an inventory of robotics parts. Group the following monomials into pairs of like terms: $5x^2$, $-3ab$, $x$, $\frac{1}{2}ab$, $-2x^2$, $8x$

We are organising an inventory of robotics parts. Group the following monomials into pairs of like terms:

$5x^2$, $-3ab$, $x$, $\frac{1}{2}ab$, $-2x^2$, $8x$

Solve

The numerical value of a monomial

To calculate the numerical value of a monomial, substitute each letter with its value (in parentheses if it is negative) and operate following the order of operations: first the power, then the multiplication.

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Calculate the numerical value of the monomial $M(x) = -5x^2$ for the indicated values of the variable: a) $x = 2$ b) $x = -1$ c) $x = 0$

Calculate the numerical value of the monomial $M(x) = -5x^2$ for the indicated values of the variable:

  1. a) $x = 2$
  2. b) $x = -1$
  3. c) $x = 0$
Solve
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Work out the numerical value of the following monomials for the values of the variables given in each case: a) $P(x, y) = -3x^2y$ for $x = -2$, $y = 5$ b)…

Work out the numerical value of the following monomials for the values of the variables given in each case:

  1. a) $P(x, y) = -3x^2y$ for $x = -2$, $y = 5$
  1. b) $Q(a, b) = \frac{2}{3}a^3b^2$ for $a = 3$, $b = -1$
Solve
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It is known that the numerical value of the monomial $M(x, y) = -5x^a y^b$ is $-320$ when $x=2$ and $y=2$. Furthermore, it is known that the relative degree with respect…

It is known that the numerical value of the monomial $M(x, y) = -5x^a y^b$ is $-320$ when $x=2$ and $y=2$. Furthermore, it is known that the relative degree with respect to the variable $x$ is twice the relative degree with respect to $y$.

Find the exponents $a$ and $b$, justifying the steps followed.

Solve

Adding and subtracting like monomials

$$4x + 2x - x = (4 + 2 - 1)x = 5x$$ Blocks of x² that combine and a block of x that cannot be combined with them. x² x² + x = 2x² + x cannot be combined into a single monomial: x² and x are not like monomials
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Simplify the following algebraic expressions by adding and subtracting like monomials: a) $4x + 2x - x$ b) $5a^2 - 3a^2 + 7a^2$ c) $3ab + ab - 2ab$

Simplify the following algebraic expressions by adding and subtracting like monomials:

  1. a) $4x + 2x - x$
  2. b) $5a^2 - 3a^2 + 7a^2$
  3. c) $3ab + ab - 2ab$
Solve
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A content creator is analysing the growth of their social media. The number of "Likes" on their photos is given by the monomial $8x^2y$, and the number of "Shares" by…

A content creator is analysing the growth of their social media. The number of "Likes" on their photos is given by the monomial $8x^2y$, and the number of "Shares" by $3x^2y$. During the last month, they received an extra number of views equivalent to $\frac{1}{2}x^2y$.

Calculate the simplified algebraic expression representing the total interaction by adding the three items.

Solve

Multiplying and dividing monomials

A Dominican content creator adds up their "likes" on photos and videos because they are like terms. But sometimes you have to multiply or divide monomials, for example to find areas.

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Perform the following monomial multiplications and simplify the result: a) $3 \times (5x^4)$ b) $(-2x^2) \times (4x)$ c) $(3a) \times (2b)$

Perform the following monomial multiplications and simplify the result:

  1. a) $3 \times (5x^4)$
  2. b) $(-2x^2) \times (4x)$
  3. c) $(3a) \times (2b)$
Solve
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In a strategy video game, your base's energy increases according to the following monomial operation. Simplify the expression to a single monomial: $$(12x^5 \times 3x^2)…

In a strategy video game, your base's energy increases according to the following monomial operation. Simplify the expression to a single monomial:

$$(12x^5 \times 3x^2) : (9x^4)$$

What is the degree of the resulting monomial?

Solve
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Simplify the following expression combining powers and divisions of monomials: $$\frac{(-2a^3b)^2 \times 5ab^4}{10a^4b^3}$$

Simplify the following expression combining powers and divisions of monomials:

$$\frac{(-2a^3b)^2 \times 5ab^4}{10a^4b^3}$$
Solve
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Fill in the gaps with the required monomial to make the equalities correct: a) $7x^3y + \dots \dots = 10x^3y$ b) $(-2ab^2) \times (\dots \dots) = 12a^3b^2$ c)…

Fill in the gaps with the required monomial to make the equalities correct:

  1. a) $7x^3y + \dots \dots = 10x^3y$
  1. b) $(-2ab^2) \times (\dots \dots) = 12a^3b^2$
  1. c) $\frac{15x^4y^2}{\dots \dots} = 3x^2y$
Solve

Combined expressions and common factor

When there are several operations, follow the order of operations: parentheses and powers, then multiplications and divisions (from left to right), and finally additions and subtractions.

To factor out the common factor in a sum of monomials, find the greatest common factor of the coefficients and, for each letter, the smallest exponent that appears in all the terms.

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Simplify the following expression involving monomials as far as possible, applying the laws of indices and the order of operations: $$\frac{(-3x^2y^3)^2 \times…

Simplify the following expression involving monomials as far as possible, applying the laws of indices and the order of operations:

$$\frac{(-3x^2y^3)^2 \times (2x^4y)^3}{(-6x^3y^2)^2}$$

Express the result as a single monomial.

Solve
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Factorise the following algebraic expression by taking out the highest common factor of the terms. Take special care with fractional coefficients: $$\frac{4}{9}a^5b^2 -…

Factorise the following algebraic expression by taking out the highest common factor of the terms. Take special care with fractional coefficients:

$$\frac{4}{9}a^5b^2 - \frac{8}{27}a^3b^4 + \frac{2}{3}a^3b^2$$
Solve
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Find the degree of this "chained" monomial and simplify it to its simplest form: $$P(x) = x \times (2x^2)^3 : \left( \frac{1}{4}x^4 \right) + (-5x^3) \times (-2x^0)$$…

Find the degree of this "chained" monomial and simplify it to its simplest form:

$$P(x) = x \times (2x^2)^3 : \left( \frac{1}{4}x^4 \right) + (-5x^3) \times (-2x^0)$$

Are the terms resulting from the sum like terms? Justify your answer.

Solve

Monomials in areas, perimeters, and phrases

The dimensions of a figure can be monomials. The area of a rectangle with base $5x$ and height $3x$ is $5x \cdot 3x = 15x^2$. The perimeter of a polygon is obtained by adding its sides, which are like monomials if they are equal monomials.

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Look at the following regular hexagon whose side measures $x$ meters. Write the monomial representing its perimeter and calculate its value if each side were $4.5$ cm.

Look at the following regular hexagon whose side measures $x$ meters. Write the monomial representing its perimeter and calculate its value if each side were $4.5$ cm.

x
Solve
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Find the monomial expressing the area of the following rectangle intended for a gaming area in a shopping center:

Find the monomial expressing the area of the following rectangle intended for a gaming area in a shopping center:

GAMING AREA Area = ? 5x 3x
Solve
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Translate the following phrases into algebraic language using a single monomial: a) Double the cube of a number $x$. b) Half the product of two numbers $a$ and $b$. c)…

Translate the following phrases into algebraic language using a single monomial:

  1. a) Double the cube of a number $x$.
  2. b) Half the product of two numbers $a$ and $b$.
  3. c) Three times the square of the distance $d$.
Solve
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Find the monomial representing the area of the following shaded region, which is part of the design of a new skatepark. Express the result in its simplest form.

Find the monomial representing the area of the following shaded region, which is part of the design of a new skatepark. Express the result in its simplest form.

5x² 3y
Solve
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Look at the following figure formed by two adjacent rectangles. a) Write the monomial that represents the area of each rectangle separately. b) Write the polynomial that…

Look at the following figure formed by two adjacent rectangles.

  1. a) Write the monomial that represents the area of each rectangle separately.
  2. b) Write the polynomial that represents the total area.
  3. c) Factor out the common factor in the expression for the total area.
A₁ A₂ 4a 2x 3y
Solve
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Calculate the monomial that represents the perimeter and the polynomial that represents the shaded area of the following composite figure (a large square with side…

Calculate the monomial that represents the perimeter and the polynomial that represents the shaded area of the following composite figure (a large square with side length $3x$ from which four identical small squares with side length $y$ have been cut out at its corners):

3x y y

Simplify the expressions as much as possible.

Solve

Patterns and problems with monomials

A sequence of figures that grows regularly is described with an expression in $n$ (the position). If each figure always has the same number of squares more than the previous one, the expression has the form $an + b$: a monomial in $n$ plus a constant term.

Costs can also be expressed with algebraic expressions. If renting a court costs $C = 360t + 120l$ pesos, among three friends each one pays $\dfrac{360t + 120l}{3} = 120t + 40l$.

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Observe the following sequence of patterns made of small squares. The first term ($n=1$) has 4 squares, the second ($n=2$) has 7, and the third ($n=3$) has 10. a)…

Observe the following sequence of patterns made of small squares. The first term ($n=1$) has 4 squares, the second ($n=2$) has 7, and the third ($n=3$) has 10.

n = 1 4 squares n = 2 7 squares n = 3 10 squares
  1. a) Determine the expression that represents the number of squares in terms of position $n$, knowing that the relationship is linear (a monomial in $n$ plus a constant term).
  1. b) How many squares will the pattern in position $n=150$ have?
  1. c) If a pattern has 91 squares, what position $n$ does it occupy in the sequence?
Solve
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In the following "product pyramid", each brick is the result of multiplying the two monomials directly below it. Complete the missing spaces by finding the monomials…

In the following "product pyramid", each brick is the result of multiplying the two monomials directly below it. Complete the missing spaces by finding the monomials $A$, $B$ and $C$.

× × × 36x⁷y⁵ A 6x³y³ 3x²y B C
Solve
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Three friends rent a padel court. The total cost is given by the algebraic expression $C(t, l) = 360t + 120l$, where $t$ is the time in hours and $l$ is the number of…

Three friends rent a padel court. The total cost is given by the algebraic expression $C(t, l) = 360t + 120l$, where $t$ is the time in hours and $l$ is the number of rented rackets.

  1. a) If they decide to split the cost equally, write the algebraic expression representing what each person has to pay.
  1. b) If a fourth friend joins the group, the total cost of the rackets increases (there are now $l+1$) and the expense is divided by four. Write the new expression for the individual payment.
  1. c) If the playing time is $1.5$ hours and each person rents their own racket, how many pesos does each of the three original friends save when the fourth player joins?
Solve

Back to the beginning: in the monomial $7x^2y$, the coefficient is $7$, the literal part is $x^2y$, and its degree is $2 + 1 = 3$.

Summary

See all the exercises in this section