SOLUTION: I want to solve {{{x^2+3x-4=0}}} by "completing the square", I have a textbook and some animations but I just do not get it. I had a problem with quadratic formula and I found an e
Question 141031: I want to solve by "completing the square", I have a textbook and some animations but I just do not get it. I had a problem with quadratic formula and I found an example on this website that just made that click for me. I am hoping someone can do the same with "complete the square". Thanks in advance for you explanation. Answer by stanbon(75887) (Show Source):
You can put this solution on YOUR website! solve by "completing the square",
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x^2+3x+? = 4+?
Square [(1/2)3] and add it to the left and right side to get:
x^2+3x + [(1/2)3]^2 = 4 + [(1/2)3]^2
Simplify both sides:
(x+(3/2))^2 = 4 + (3/2)^2
(x+(3/2))^2 = 25/4
Take the square root of both sides to get:
(x+(3/2)) = +- 5/2
x = (-3/2) + (5/2) or x = (-3/2) - (5/2)
x = 1 or x = 4
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Cheers,
Stan H.
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