Faktor dari a.x^2+x-12=0

x^2 + x - 12
= x^2 + 4x - 3x - 12
= x(x +4) -3(x + 4)
= (x - 3)(x + 4)

Langsung aja y

x² + x - 12 = 0

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

x = -4 dan x = 3

Semoga berguna +_+