Which one of the following is a factor of x3 + 5x + 18?
If x - a is a factor of x3 + 5x + 18
Then value of a3 + 5a + 18 will be zero
First we substitute x = 2
(2)3 + 5(2) + 18 = 36 ≠ 0
Now x = -2
(-2)3 + 5(-2) + 18 = 0
So this is a solution of equation and (x + 2) is a root of this polynomial
Next if we check the remaining options no one will satisfy the polynomial