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41 votes
41 votes
Which two values of x are roots of the polynomial below?x2 + 5x + 9I A. x =-5+7-112B. =15-$172O C. X =5 + √172I D. X =-5 - 6

User Hotenov
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1 Answer

8 votes
8 votes

Given:


x^2+5x+9

To solve this equation, we will be needing to use the quadratic formula:


x=\frac{-b\pm\sqrt[]{b^2-4ac}}{2a}

From the given equation, we know that:

a = 1

b = 5

c = 9

Substitute the given data to the quadratic equation


x=\frac{-b\pm\sqrt[]{b^2-4ac}}{2a}
=\frac{-5\pm\sqrt[]{(5)^2-4(1)(9)}}{2(1)}
=\frac{-5\pm\sqrt[]{25^{}-36}}{2}
=\frac{-5\pm\sqrt[]{-11}}{2}

Separate the plus minus sign


x=\frac{-5+\sqrt[]{-11}}{2}
x=\frac{-5-\sqrt[]{-11}}{2}

Therefore, the final answer would be A and F.

User Steve Padmore
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3.0k points