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Richie is solving the equation x^2 −12x = 28 by completing the square. What number should he add to both sides of the equation to complete the square?A) 6 B) 12C) 36D) 34

User Tom Riley
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1 Answer

19 votes
19 votes

The given equation is:


x^2-12x=28

Add (12/2)^2=36 on both sides of the equation.


\begin{gathered} x^2-12x+((12)/(2))^2=28+((12)/(2))^2 \\ x^2-12x+36^{}=28+36 \\ (x+6)^2=64 \end{gathered}

Therefore, adding 36 to both sides of the equation complete the square.

Hence, option C is correct.

User MihaiC
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