Respuesta :

12x^2+x-8 - (4x^2-1)
12x^2+x-8-4x^2+1
8x^2 + x - 7 =0

8x^2 + 8x - 7x -7 = 0
8x ( x + 1 ) - 7 ( x + 1 ) = 0
(8x - 7) (x + 1) =0
8x -7 = 0
x + 1 = 0
x = 7/8 and x = -1