(10+2x)*x=56

Solution for (10+2x)*x=56 equation:

(10+2x)*x=56

We move all terms to the left:

(10+2x)*x-(56)=0

We add all the numbers together, and all the variables

(2x+10)*x-56=0

We multiply parentheses

2x^2+10x-56=0

a = 2; b = 10; c = -56;
Δ = b2-4ac
Δ = 102-4·2·(-56)
Δ = 548
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:

$\sqrt{\Delta}=\sqrt{548}=\sqrt{4*137}=\sqrt{4}*\sqrt{137}=2\sqrt{137}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(10)-2\sqrt{137}}{2*2}=\frac{-10-2\sqrt{137}}{4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(10)+2\sqrt{137}}{2*2}=\frac{-10+2\sqrt{137}}{4}
$