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

Solution for (2x+1)(x-1)=2 equation:

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

We move all terms to the left:

(2x+1)(x-1)-(2)=0

We multiply parentheses ..

(+2x^2-2x+x-1)-2=0

We get rid of parentheses

2x^2-2x+x-1-2=0

We add all the numbers together, and all the variables

2x^2-1x-3=0

a = 2; b = -1; c = -3;
Δ = b2-4ac
Δ = -12-4·2·(-3)
Δ = 25
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{25}=5$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-1)-5}{2*2}=\frac{-4}{4}
=-1
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-1)+5}{2*2}=\frac{6}{4}
=1+1/2
$