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7 votes
7 votes
Solve the quadratic equation by completing the square: x² – 10 + 16 = 0

User Jeff Padgett
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1 Answer

16 votes
16 votes

Answer:

x = 8 or x = 2

Step-by-step explanation:

Given the below quadratic equation;


x^2-10x+16=0

To solve the above using the completing the squares method, we'll have to follow the below-outlined steps;

1. Subtract 16 from both sides of the equation;


\begin{gathered} x^2-10x+16-16=0-16 \\ x^2-10x=-16 \end{gathered}

2. Add 1/2 of the coefficient of x squared to both sides of the equation;


\begin{gathered} x^2-10x+((-10)/(2))^2=-16+((-10)/(2))^2 \\ x^2-10x+25=-16+25 \\ x^2-10x+25=9 \end{gathered}

3. Factor the left-hand side of the equation into a perfect square;


(x-5)^2=9

4. Let's go ahead and take the square root of both sides and solve for x;


\begin{gathered} x-5=\sqrt[]{9} \\ x-5=3 \\ x=8 \\ Or \\ x-5=-3 \\ x=5-3 \\ x=2 \end{gathered}

User Manish S
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