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Verified Answer :

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:

(x-4) is a factor

Step-by-step 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

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