x+(x*10/100)*6=1600

Solution for x+(x*10/100)*6=1600 equation:

x+(x*10/100)*6=1600

We move all terms to the left:

x+(x*10/100)*6-(1600)=0

We add all the numbers together, and all the variables

x+(+x*10/100)*6-1600=0

We multiply parentheses

60x^2+x-1600=0

a = 60; b = 1; c = -1600;
Δ = b2-4ac
Δ = 12-4·60·(-1600)
Δ = 384001
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(1)-\sqrt{384001}}{2*60}=\frac{-1-\sqrt{384001}}{120}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(1)+\sqrt{384001}}{2*60}=\frac{-1+\sqrt{384001}}{120}
$