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36 votes
Find the solutions for the quadratic equation by completing the square.
x ^(2) + 18x = 63

Find the solutions for the quadratic equation by completing the square.x ^(2) + 18x-example-1
User HighwayJohn
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1 Answer

23 votes
23 votes

Completing the square


x^2+18x=63
\begin{gathered} x^2+18x+((18)/(2))^2=63+((18)/(2))^2 \\ x^2+18x+81=63+81 \\ x^2+18x+81=144 \\ (x+9)^2=144 \\ \end{gathered}
\begin{gathered} (x+9)=\sqrt[]{144} \\ x+9=\pm12 \\ x_1=-12-9 \\ x_1=-21 \\ \\ x_2=12-9 \\ x_2=3 \end{gathered}

The answer would be -21, 3

User White Dragon
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