use quadratic formula to show the trinomial is not factorable, and explain.?

Question

4x^2 - x - 12

Answer 1

just plug those numbers into the quadratic formula, which is:
-b plus or minus the square root of b sqared - 4ac, all over 2a. Specifically, for your problem, it would be:

-1 plus or minus the square root of 1squared minus 4(12)(4) all over 8

Answer 2

Just compute b²-4ac = 1+4(4)(12) = 193.
Since this is not a square, the trinomial is not
factorable.

Answer 3

The discriminant (The part under the radical) is sqrt 193. Generally, the result is not factorable if the discriminant is irrational (or negative)