[(4x+1)(3x+2)][(12x-1)(x+1)]=4

=>(12x^2+11x+2)(12x^2+11x-1)=4

dat 12x^2+11x-1=ythi y(y+3)=4

=>Y^2+3y-4=0

=>y^2+4y-y-4=0

=>y(y+4)-(y+4)=0=>9y-1)(y-4)=0

ban tu giai tiep nha

(4x+1)(12x−1)(3x+2)(x+1)−4

=[(4x+1)(3x+2)][(12x−1)(x+1)]−4

=(12x2+11x+2)(12x2+11x−1)−4

Đặt 12x2 + 11x -1 = a, ta được:

=(a+3)a−4

=a2+3a−4

=a2−a+4a−4

=a(a−1)+4(a−1)

=(a−1)(a+4)

=(12x2+11x−1−1)(12x2+11x−1+4)

=(12x2+11x−2)(12x2+11x+3)