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Solve equation by completing the square.

Solve equation by completing the square.-example-1

1 Answer

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Answer:

x=3 and x=5

Explanation:

x2−8x+15=0

To solve the equation, factor x2−8x+15 using formula x2+(a+b)x+ab=(x+a)(x+b). To find a and b, set up a system to be solved.

a+b=−8ab=15

Since ab is positive, a and b have the same sign. Since a+b is negative, a and b are both negative. List all such integer pairs that give product 15.

−1,−15−3,−5

Calculate the sum for each pair.

−1−15=−16−3−5=−8

The solution is the pair that gives sum −8.

a=−5b=−3

Rewrite factored expression (x+a)(x+b) using the obtained values.

(x−5)(x−3)

To find equation solutions, solve x−5=0 and x−3=0.

x=5x=3

hope it helps :)

User Michael Grogan
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