so we're talking

$$\frac{1}{12}x^2-\frac{2}{3}x=4$$

start by multiplying both sides by 12 and getting all the terms on the left side and 0 on the right side.

Then factor that quadratic polynomial on the left via one of the methods you've learned. Here if you need a review.

Then just apply the zero product property to your two factors to obtain your two solutions.