In order to solve this, we need to solve for B. We do this by getting it alone on one side. First, however, we need to multiply the right side of the equation out to simply:
(3x-4)(x+2) = 3x^2 + 2x - 8
So now we have:
3x^2 + B - 8 = 3x^2 -2x - 8
B = -2x
We can double check this by plugging it back into the original equation.
