For each equation, first use the distributive property in reverse to rewrite the left side as one product. Then find the missing value.
a) \(17\times5+17\times x=170\)
b) \(4\times y-4\times15=40\)
c) \(13\times12-x\times12=60\)
Hints
- Identify the common factor in the two terms on the left side of each equation.
- Your rewritten equation must show that common factor outside parentheses.
- Only after rewriting should you use inverse operations to find the missing value.
Solution
1. For a), factor out \(17\): \(17\times(5+x)=170\). Since \(170\div17=10\), \(5+x=10\), so \(x=5\).
2. For b), factor out \(4\): \(4\times(y-15)=40\). Since \(40\div4=10\), \(y-15=10\), so \(y=25\).
3. For c), factor out \(12\): \((13-x)\times12=60\). Since \(60\div12=5\), \(13-x=5\), so \(x=8\).
Answer
a) \(17\times(5+x)=170\); \(x=5\)
b) \(4\times(y-15)=40\); \(y=25\)
c) \((13-x)\times12=60\); \(x=8\)