Answer
$$\frac{4x+1}{b-a}$$
Work Step by Step
Simplifying the fraction, we find:
$$\frac{\left(a+b\right)\left(8x+2\right)}{2\left(b^2-a^2\right)} \\ \frac{\left(a+b\right)\left(4x+1\right)}{\left(b+a\right)\left(b-a\right)} \\ \frac{4x+1}{b-a}$$