Tìm x, biết: (x + 2)*(x + 3) - (x - 2)*(x*(-5)) = 6

Tìm x, biết
a) (x+2)*(x+3)-(x-2)*(x*(-5))=6
b) (3x+2)*(2x+9)-(x+2)*(6x+1)=(x+1)-(x-6)
c) 3(2x-1)(3x-1)-(2x-3)(9x-1)=0