Answer
$\frac{2(a^{2}+a-10)}{(a+5)(a+5)(a+1)}$
Work Step by Step
Original Equation
$\frac{a}{a^{2}+10a+25}$ - $\frac{4-a}{a^{2}+6a+5}$
Factor Denominator
$\frac{a}{(a+5)(a+5)}$ - $\frac{4-a}{(a+5)(a+1)}$
Find LCD: (a+5)(a+5)(a+1)
Add numerators
$\frac{a(a+1)-(4-a)(a+5)}{(a+5)(a+5)(a+1)}$
Simplify
$\frac{2a^{2}+2a-20}{(a+5)(a+5)(a+1)}$
Factor
Answer: $\frac{2(a^{2}+a-10)}{(a+5)(a+5)(a+1)}$
