x2+4x+4-(x+2)(2x-1)=0

Solution for x2+4x+4-(x+2)(2x-1)=0 equation:

x2+4x+4-(x+2)(2x-1)=0

We add all the numbers together, and all the variables

x^2+4x-(x+2)(2x-1)+4=0

We multiply parentheses ..

x^2-(+2x^2-1x+4x-2)+4x+4=0

We get rid of parentheses

x^2-2x^2+1x-4x+4x+2+4=0

We add all the numbers together, and all the variables

-1x^2+x+6=0

a = -1; b = 1; c = +6;
Δ = b2-4ac
Δ = 12-4·(-1)·6
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*-1}=\frac{-6}{-2}
=+3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1)+5}{2*-1}=\frac{4}{-2}
=-2
$