Question

x2 + x - 12 = 0

Answer 1

to factor, you want to think of two numbers that multiply to -12, and add up to 1
These numbers are -3 and 4
So now we can factor this:
\[x^{2} +x-12 = (x-3)(x+4) = 0\]
Thus are two solutions are x = 3, and x = -4

Answer 2

-1 +/- radical 49 -1 +/- 7
x_1,_2 = -------------- = --------- = -4 and 3
2 2