SOLUTION: Solve by completing the square: x^2+4x-5=0

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Question 178395This question is from textbook
: Solve by completing the square: x^2+4x-5=0 This question is from textbook

Answer by jim_thompson5910(35256)   (Show Source): You can put this solution on YOUR website!

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 .


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Now let's solve


Start with the given equation.


Add to both sides.


Combine like terms.


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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