Simplifying Algebraic Expressions

Site: Saylor Academy
Course: GKT101: General Knowledge for Teachers – Math
Book: Simplifying Algebraic Expressions
Printed by: Guest user
Date: Sunday, May 19, 2024, 10:19 PM

Description

You can use two main tools to simplify or rewrite algebraic expressions: combining like terms and using the distributive property. Watch this lecture series and complete the interactive exercises to practice these skills.

Combining like terms with negative coefficients & distribution

Combining like terms with negative coefficients

Combining like terms with rational coefficients

Combining like terms with negative coefficients - Questions

1. Combine the like terms to create an equivalent expression: −n+(−4)−(−4n)+6

2. Combine the like terms to create an equivalent expression:  -2 x-x+8

3. Combine the like terms to create an equivalent expression: 2 s+(-4 s)

4. Combine the like terms to create an equivalent expression: -3 x-6+(-1)

5. Combine the like terms to create an equivalent expression: 2 r+1+(-4 r)+7

6 . Combine the like terms to create an equivalent expression: −5r+8r+5

7. Combine the like terms to create an equivalent expression: r+(−5r)

Answers

1. Combine the n terms:

\begin{aligned}
-n+(-4)-(-4 n)+6 &=(-1+4) n-4+6 \\
&=3 n-4+6
\end{aligned}

Combine the numeric terms:

3 n-4+6=3 n+2

The simplified expression is 3n + 2.


2. Combine the x terms:

\begin{aligned}
-2 x-x+8 &=(-2-1) x+8 \\
&=-3 x+8
\end{aligned}

The simplified expression is  -3x + 8 .


3. Combine the s terms:

\begin{aligned}
2 s+(-4 s) &=(2-4) s \\
&=-2 s
\end{aligned}

The simplified expression is -2s.


4. Combine the numeric terms:

-3 x-6-1=-3 x-7

The simplified expression is -3x - 7.


5. Combine the r terms:

\begin{aligned}
2 r+1+(-4 r)+7 &=(2-4) r+1+7 \\
&=-2 r+1+7
\end{aligned}

Combine the numeric terms:

−2r+1+7=−2r+8

The simplified expression is -2r +8.


6. Combine the r terms:

 \begin{aligned}
-5 r+8 r+5 &=(-5+8) r+5 \\
&=3 r+5
\end{aligned}

The simplified expression is 3r + 5.


7. Combine the r terms:

\begin{aligned}
r+(-5 r) &=(1-5) r \\
&=-4 r
\end{aligned}

The simplified expression is -4r.

Combining like terms with negative coefficients & distribution - Questions

1. Simplify to create an equivalent expression. 2(−2−4p)+2(−2p−1)

Choose 1 answer:

A. −12p−6

B. -10p - 6

C. -12p+6

D. 12p-6


2. Simplify to create an equivalent expression. 1+4(6p−9)

Choose 1 answer:

A. 6p−35

B. 24p−35

C. 24p−36

D. 6p−36


3. Simplify to create an equivalent expression. 4(−15−3p)−4(−p+5)

A. −8p−80

B. −13p−80

C. −8p+80

D. 8p-80


4. Simplify to create an equivalent expression. 2−4(5p+1)

A. −20p−2

B. −5p−4

C. −20p+2

D. −5p+4

Answers

1. A. −12p−6

2. B. 24p−35

3. A. −8p−80

4. A. −20p−2

Combining like terms with rational coefficients - Questions

1. Combine like terms to create an equivalent expression.  −2.5(4x−3)


2. Combine like terms to create an equivalent expression. 1.3b+7.8−3.2b


3. Combine like terms to create an equivalent expression. -\frac{2}{3} p+\frac{1}{5}-1+\frac{5}{6} p
Enter any coefficients as simplified proper or improper fractions or integers.


4. Combine like terms to create an equivalent expression. \frac{1}{7}-3\left(\frac{3}{7} n-\frac{2}{7}\right)
Enter any coefficients as simplified proper or improper fractions or integers.

Answers

1. Use the distributive property to multiply the -2.5 into the parentheses.

= −2.5(4x−3)

= −2.5⋅(4x)+(−2.5)⋅(−3)

We expanded the expression by multiplying the -2.5 by both terms in the parentheses.

=-10x+7.5

The expanded expression is -10x+7.5.


2. Combine the coefficients of the b terms.

= =1.3b+7.8−3.2b

= (1.3−3.2)⋅b+7.8

= (−1.9)⋅b+7.8

= −1.9b+7.8

The simplified expression is −1.9b+7.8 .


3. Combine the coefficients of the p terms, and combine the constant terms.

= -\frac{2}{3} p+\frac{1}{5}-1+\frac{5}{6} p

= \left(-\frac{2}{3}+\frac{5}{6}\right) \cdot p+\frac{1}{5}-1

Group the p coefficients together, and group the numeric coefficients together.

= \left(-\frac{4}{6}+\frac{5}{6}\right) \cdot p+\frac{1}{5}-\frac{5}{5}

Rewrite −1 as -\frac{5}{5} to form common denominators.

= \left(\frac{1}{6}\right) \cdot p-\frac{4}{5}

=\frac{1}{6} p-\frac{4}{5}

The simplified expression is \frac{1}{6} p-\frac{4}{5}.


4. Use the distributive property to multiply the -3 into the parentheses.

= \frac{1}{7}-3\left(\frac{3}{7} n-\frac{2}{7}\right)

=  \frac{1}{7}+(-3) \cdot\left(\frac{3}{7} n\right)+(-3) \cdot\left(-\frac{2}{7}\right)

We expanded the expression by multiplying the -3 by both terms in the parentheses.

= \frac{1}{7}-\frac{9}{7} n+\frac{6}{7}

= -\frac{9}{7} n+\frac{7}{7}

We combined the numeric terms.

= -\frac{9}{7} n+1

The expanded expression is -\frac{9}{7} n+1.