x^2-x-20

Select the correct choice below.

(a) x^2-x-20=?

(b) The polynomial is prime.

x^2-x-20

Select the correct choice below.

(a) x^2-x-20=?

(b) The polynomial is prime.

Tutors, please sign in to answer this question.

Because a quadratic trinomial can have two solutions, x_{1} and x_{2,
}it can ve factored in the following way

x^2 -x -20 = (x -x_{1})(x-x_{2}) (when the first coefficient in the trinomial is equal 1)

x1 and x2 are factors of -20 such that x1 +x2 = -(-1) =1. It is easy to see that x1 = 5, x2 = -4.

Thus, we have x^2 - x - 20 = (x-5)(x+4)

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