Question 198634
2x^2-4x-1=0
x^2-2x-(1/2)=0 divide each side by 2
x^2-2x=.5
x^2-2x+1=1.5 completing the square.
(x-1)^2=1.5
x-1=+-sqrt(1.5)
x=1+-sqrt(1.5)
x=1-sqrt(1.5)= -0.225
x=1+sqrt(1.5)= 2.225
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It is more exact and less of a mess with decimal points and rounding if you keep it 1+-sqrt(1.5)
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Ed
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{{{graph(500,500,-10,10,-10,10,2x^2-4x-1)}}}