hey there,
y = 90 + -45x + -10x2 + 5x3
-6x + -3x = -9x y = 5(18 + -9x + 1x2 + -3x2 + x3) (-2 + x) * (3 + x) y = 5(-2(3 + x) + x(3 + x))(-3 + x) y = 5((3 * -2 + x * -2) + x(3 + x))(-3 + x) y = 5((-6 + -2x) + x(3 + x))(-3 + x) y = 5(-6 + -2x + (3 * x + x * x))(-3 + x) y = 5(-6 + -2x + (3x + x2))(-3 + x)
y = 90 + -45x + -10x2 + 5x3=
10 15
115+-45=70
X=70