P(x)=4x³+2x²-2x+7-x²-x
= 4x^3 + (2x^2 - x^2) - (2x + x) + 7
= 4x^3 + x^2 - 3x + 7
Q(x)=-4x³+x-14-2x-x²-1
= - 4x^3 - x^2 + (x - 2x) - (14 + 1)
= -4x^3 - x^2 - x - 15
P(x) = -Q(x)
4x^3 + x^2 - 3x + 7 = - (-4x^3 - x^2 - x - 15)
4x^3 + x^2 - 3x + 7 = 4x^3 + x^2 + x + 15
(4x^3 - 4x^3) + (x^2 - x^2) + ( -3x - x) + 7 - 15 = 0
-4x -8 = 0
4x + 8 = 0
x = -2