(x+5)(x-2)=x

Solution for (x+5)(x-2)=x equation:

(x+5)(x-2)=x

We move all terms to the left:

(x+5)(x-2)-(x)=0

We add all the numbers together, and all the variables

-1x+(x+5)(x-2)=0

We multiply parentheses ..

(+x^2-2x+5x-10)-1x=0

We get rid of parentheses

x^2-2x+5x-1x-10=0

We add all the numbers together, and all the variables

x^2+2x-10=0

a = 1; b = 2; c = -10;
Δ = b2-4ac
Δ = 22-4·1·(-10)
Δ = 44
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{44}=\sqrt{4*11}=\sqrt{4}*\sqrt{11}=2\sqrt{11}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(2)-2\sqrt{11}}{2*1}=\frac{-2-2\sqrt{11}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(2)+2\sqrt{11}}{2*1}=\frac{-2+2\sqrt{11}}{2}
$