Question

Which of the binomials below is a factor of this trinomial?

x2 + x - 20







A.

x - 4








B.

x + 2








C.

x - 2








D.

x + 4

Answer 1

Which of the binomials below is a factor of this trinomial?

x2 + x - 20







A.

x - 4








B.

x + 2








C.

x - 2








D.

x + 4

The answer is a). x - 4

Answer 2

(x-4) is a factor

Explanation:

`x^2 + x - 20`

To factor this trinomial , we find out two factors whose product is -20 and sum is +1

`5 * (-4)= -20`

`5+(-4)= +1`

Now we use factors 5 and -4

`x^2 +5x -4x - 20`

`(x^2 +5x)+(-4x - 20)` Take out GCF from each group

`x(x+5)-4(x+5)`

Factor out x+5

`(x+5)(x-4)`

So (x-4) is a factor