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Solve the quadratic equation by completing the square x^2+8x+11=0

User Lowitty
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1 Answer

1 vote

Answer:


x=-4\pm\sqrt5

Explanation:

So we have the equation:


x^2+8x+11=0

First, subtract 11 from both sides:


x^2+8x=-11

Now, add the c term. Divide 8 by 2 and then square it:


(x^2+8x+16)=-11

What we do to one side we must also do to the other. Thus:


(x^2+8x+16)=-11+16

Simplify:


(x^2+8x+16)=5

Perfect Square Trinomial:


(x+4)^2=5

Take the square root:


x+4=\pm\sqrt5

Subtract 4:


x=-4\pm\sqrt5

And that's our answer :)

User Shava
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5.1k points