[tex]~~~~~(x+1)(x^2 -5x +10) -12= 0\\\\\implies x^3 -5x^2 +10x +x^2 -5x +10 -12 =0\\\\\implies x^3 -4x^2 +5x -2 =0\\\\\implies x^3 -2x^2-2x^2+4x+x-2=0\\\\\implies x^2(x-2)-2x(x-2)+(x-2)=0\\\\\implies (x-2)(x^2 -2x +1)=0\\\\\implies (x-2)(x-1)^2 = 0\\\\\implies x =2 , ~~ x = 1[/tex]
