How do you solve 2x^2-2x+7=5 by completing the square?

1 Answer
Nghi N
Jul 19, 2017

x = (1 +- isqrt3)/2

Explanation:

2x^2 - 2x = - 2
x^2 - x = - 1
x^2 - x + 1/4 = - 1 + 1/4
(x - 1/2)^2 = - 3/4 = (3i^2)/4
There are 2 complex roots:
x - 1/2 = +- (isqrt3)/2
x = 1/2 +- (isqrt3)/2 = (1 +- isqrt3)/2

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