5. evaluate: $\frac{5(n + 8)-3(n + 2)}{2n + 4}$; let $n=-3$

Explanation:

Step1: Expand the numerator

First, expand $5(n + 8)-3(n + 2)$ using the distributive property. $5(n + 8)-3(n + 2)=5n+40-3n - 6=(5n-3n)+(40 - 6)=2n+34$.

Step2: Substitute $n=-3$ into the expression

The original expression becomes $\frac{2n + 34}{2n+4}$. Substitute $n = - 3$ into it. When $n=-3$, the numerator is $2\times(-3)+34=-6 + 34=28$, and the denominator is $2\times(-3)+4=-6 + 4=-2$.

Step3: Calculate the value of the fraction

The value of the fraction $\frac{28}{-2}=-14$.

Answer:

$-14$