7.x(2+x)-7.x(x+3)=14
14x+7x2-7x2-21x=14
14x-21x=14
-7x=14
x=14/-7
x=-2
7x(2+x)-7.x(x+3)=14
2x(2+x)(x+3) = 14:(-7)
7x = -2
7x = -2 . 7
7x = -14
x = -14 : 7
x = -2