Answers

2016-07-27T21:15:27+08:00
X^2 - 8x + 16 - 81 = 0
x^2 - 8x + 16 = 81
(x-4)^2 = 81
sqroot (x-4)^2 = sqroot (81)
x - 4 = + - 9
x=13
x= - 5


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