How do you solve using the completing the square method 5x²+8x-2=0?

1 Answer
Nghi N
Jul 13, 2017

x = (-4 + 3sqrt2)/5
x = (-4 - 3sqrt2)/5

Explanation:

Divide by 5 -->
x^2 + (8x)/5 = 2/5
x^2 + (8x)/5 + 16/25 = 2/5 + 16/25
(x + 4/5)^2 = 18/25
x + 4/5 = +- sqrt18/5 = +- (3sqrt2)/5
x = - 4/5 +- (3sqrt2)/5 = (-4 +- 3sqrt5)/5
x1 = (-4 + 3sqrt2)/5
x2 = (-4 - 3sqrt2)/5

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