10(8+x)x=4

Solution for 10(8+x)x=4 equation:

10(8+x)x=4

We move all terms to the left:

10(8+x)x-(4)=0

We add all the numbers together, and all the variables

10(x+8)x-4=0

We multiply parentheses

10x^2+80x-4=0

a = 10; b = 80; c = -4;
Δ = b2-4ac
Δ = 802-4·10·(-4)
Δ = 6560
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:

$\sqrt{\Delta}=\sqrt{6560}=\sqrt{16*410}=\sqrt{16}*\sqrt{410}=4\sqrt{410}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(80)-4\sqrt{410}}{2*10}=\frac{-80-4\sqrt{410}}{20}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(80)+4\sqrt{410}}{2*10}=\frac{-80+4\sqrt{410}}{20}
$