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Answer 1 · 2016-04-22T16:25:52

$x=2, -1$

$x^2-x-2=0$

$x^2-x-2+2=0+2$

$x^2-x=2$

Add the square of -1/2 (the coefficient of the $-x$ divided by 2) to both sides. Remember, the standard form is $x^2 + 2ax + a^2$
$x^2-x+1/4=2+1/4$

Factor the left side of the equation
$(x-1/2)(x-1/2)=2 1/4$
$(x-1/2)^2 =2 1/4$

$sqrt((x-1/2)^2) =sqrt(2 1/4)$

$(x-1/2)=+-1 1/2$

$x=1/2+-1 1/2=2,-1$