SOLUTION: I need to solve x^2+6x-16=0 by completing the square

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Question 600305: I need to solve x^2+6x-16=0 by completing the square
Answer by jim_thompson5910(35256)   (Show Source): You can put this solution on YOUR website!
First, let's complete the square.



Start with the given expression.


Take half of the coefficient to get . In other words, .


Now square to get . In other words,


Now add and subtract . Make sure to place this after the "x" term. Notice how . So the expression is not changed.


Group the first three terms.


Factor to get .


Combine like terms.


So after completing the square, transforms to . So .


So is equivalent to .


Now let's solve



Start with the given equation.


Add 25 to both sides


Take the square root of both sides.


or Break up the "plus/minus" to form two equations.


or Take the square root of to get .


or Subtract from both sides.


or Combine like terms.


--------------------------------------


Answer:


So the solutions are or .

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