Răspuns:
(x-5)[9x-4(5x-10-3x+12)+3]=x^2 + 2x + 1
(x-5)[9x-4(2x+2)+3]=x^2 + 2x + 1
(x-5)(9x-8x-8+3)=x^2 + 2x + 1
(x-5)(x-5)=x^2 + 2x + 1
x^2 - 10x + 25 = x^2 + 2x + 1
-10x - 2x = 1 - 25
-12x = -24
x = 2