How do you complete the square to solve #4y^2 + 8y - 36 = 0#?

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Answer 1 · 2018-03-03T06:51:43

#color(red)(x = 2.1623, - 4.1623#

#4y^2 + 8y - 36= 0#

#4 (x^2 + 2x -9) = 0#

#x^2 + 2x = 9#

Add 1 to both sides.

#x^2 + 2x + 1 = 9 + 1 = 10#

#(x+1)^2 = (sqrt10)^2#

#x + 1 = +-sqrt10#

#x = +-sqrt10 - 1#

#color(red)(x = 2.1623, - 4.1623#