Sagot :
y = (x+2)(x-6)(x+7)
(x+2)(x+7)
x^2 - 6x + 2x - 12
x^2 - 4x - 12
(x^2 - 4x - 12)(x + 7)
x^3 + 7x^2 - 4x^2 - 28x - 12x - 84
x^3 + 3x^2 - 40x - 84
y = x^3 + 3x^2 - 40x - 84
[tex]y = (x + 2) (x -6) (x + 7) \\ \\ i.e, y = (x+2) (x^2 - x - 42) \\\\ => y = x^3 + 3x^2 - 40x - 84[/tex]