Question 693848
5x^2-2x=7
Divide by 5 to make the coefficient of x^2 = 1
{{{x^2 - (2/5)x = 7/5}}}
a = 1, b = -2/5
Add (b/2)^2 = 1/25
{{{x^2 - (2/5)x +1/25 = 7/5 + 1/25}}}

{{{x^2 - (2/5)x +1/25 = 36/25}}}
{{{(x - 1/5)^2 = (6/5)^2}}}
x - 1/5 = ± 6/5
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x = 1/5 + 6/5 = 7/5
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x = 1/5 - 6/5 = -1