Answer:
a=-4 and b=6
Explanation:

First, add the fractions by finding the common denominator.
In this case, (x-8)(x+4).

Therefore, the numerators are equal:

Simplify:

Now match the coefficients.

Solve the system of equations. I'll use substitution, but you can also use elimination if you prefer.

Therefore, a=-4 and b=6.