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 rational coefficients - Questions
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 \(-\frac{9}{7} n+1\).