Question

1. $-5(x + 2y) + 15(x + 2y)$; $x = 7$ and $y = -7$

Explanation:

Step1: Simplify the expression

Notice that \(-5(x + 2y)\) and \(15(x + 2y)\) are like terms. Combine them: \((-5 + 15)(x + 2y)=10(x + 2y)\)

Step2: Substitute \(x = 7\) and \(y=-7\)

First, calculate \(x + 2y\): \(7+2\times(-7)=7 - 14=-7\)
Then, multiply by 10: \(10\times(-7)=-70\)

Answer:

\(-70\)