Question

Which shows one way to determine the factors of x3 + 11x2 – 3x – 33 by grouping?

x2(x + 11) + 3(x – 11)
x2(x – 11) – 3(x – 11)
x2(x + 11) + 3(x + 11)
x2(x + 11) – 3(x + 11)

Answer 1

x^3 + 11x^2 – 3x – 33 = (x^3 + 11x^2) + ( -3x - 33 )
= x^2(x + 11) - 3(x + 11)
= (x + 11)(x^2 - 3).

So the correct choice is: x^2(x + 11) – 3(x + 11).