(х +6)(х - 1)-(х +3)(х - 4)=5x
x2-x+6x-6-(x2-4x+3x-12)=5x
x2-x+6x-6-(x2-x-12)=5x
x2-x+6x-6-x2+x+12=5x
6x+6=5x
6x-5x=-6
X=-6
(х +6)(х - 1)-(х +3)(х - 4)=5x
x2-x+6x-6-(x2-4x+3x-12)=5x
x2-x+6x-6-(x2-x-12)=5x
x2-x+6x-6-x2+x+12=5x
6x+6=5x
6x-5x=-6
X=-6