Answer
$-\frac{2}{a + 3}$
Work Step by Step
To add or subtract rational expressions, we need to make sure that the expressions have the same denominator. The two rational expressions do have the same denominator, so we can proceed to evaluate the expression.
Rewrite the two fractions as one with the same denominator:
$\frac{(3a - 6) - (7a + 8)}{(2a + 7)(a + 3)}$
Combine like terms in the numerator:
$\frac{-4a - 14}{(2a + 7)(a + 3)}$
Factor out what is common in the numerator:
$\frac{-2(2a + 7)}{(2a + 7)(a + 3)}$
We can cancel out the $2a + 7$ in the numerator and denominator:
$-\frac{2}{a + 3}$
