What value is a discontinuity of quantity x squared plus 3 x minus 4 divided by quantity x squared plus x minus 12

(x² + 3x + 4) / (x² + x - 12)

Note that you can't divide by zero, and discontinuities are a result of that. We are looking for:

x² + x - 12 = 0

(x + 4) (x - 3) = 0

x = 3, - 4

a. is one of those values, and is the answer.