Solve For $x$ Assume That $a$ And $b$ Represent Positive Real Numbers $(3 x-4 b)^{2}=7 a$

Multiple Choice

Solve for $x$ . Assume that $a$ and $b$ represent positive real numbers.
- $(3 x-4 b) ^{2}=7 a$

A) $\left\{\frac{\sqrt{16 b^{2}+7 a}}{9}, \frac{-\sqrt{16 b^{2}-7 a}}{9}\right\}$

B) $\left\{\frac{4 b+\sqrt{7 a}}{3}, \frac{4 b-\sqrt{7 a}}{3}\right\}$

C) $\left\{\frac{4 b+\sqrt{7 a}}{3} \cdot \frac{-\sqrt{4 b-7 a}}{3}\right\}$

D) $\left\{\frac{4 b+7 a}{3}, \frac{-4 b-7 a}{3}\right\}$