A= x^2 -4x
B= x^2 + 3x
C= x -2x^2 +3x = -2x^2 +3x +x= -2x^x +4x
D= 5x^3 - 5x -x x2 = 5x^3 -5x -2x = 5x^3 -7x
E= 12x^2 -9x + 2x(4 -6x) = 12x^2 -9x +8x - 12x^2 = 12x^2 -12x^2 +8x -9x = -x
F= -8x +12x^2 +7 +3x +15= 12x^2 +3x -8x +7 +15 = 12x^2 -5x +22
