SOLUTION: Solve 7x^2+28x=49 by completing the square. I know you use the formula (b/2)^2 right?

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Question 243530: Solve 7x^2+28x=49 by completing the square. I know you use the formula (b/2)^2 right?
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
7x%5E2%2B28x=49 Start with the given equation.


7%28x%5E2%2B4x%29=49 Factor out the GCF 7 from the left side.


x%5E2%2B4x=49%2F7 Divide both sides by 7.


x%5E2%2B4x=7 Reduce


x%5E2%2B4x%2Bhighlight%284%29=7%2Bhighlight%284%29 Take half of the 'x' coefficient and square it to get 4. Add this number to both sides.


%28x%2B2%29%5E2=11 Factor the left side and combine like terms on the right.


x%2B2=%22%22%2B-sqrt%2811%29 Take the square root of both sides.


x=-2%2B-sqrt%2811%29 Subtract 2 from both sides to isolate 'x'.


So the solutions are x=-2%2Bsqrt%2811%29 or x=-2-sqrt%2811%29