Question

Which one of the following is not a factor of $x^3$+ 2$x^2$ + x?

• A. x + 2
• B. x + 1
• C. x
• D. x (x + 1)

Answer 1

The correct option is A

x + 2

Let P(x) = $x^3$+ 2$x^2$ + x

For x + 2 to be a factor of P(x), P(-2) should be zero by factor theorem.

For P(-2) = ${(-2)}^3$+ 2${(-2)}^2$ + (-2)

= -8 + 8 -2

= -2

Since P(-2) $\ne$ 0, x + 2 is not a factor.