x*(10.7/100)=31

Solution for x*(10.7/100)=31 equation:

x*(10.7/100)=31

We move all terms to the left:

x*(10.7/100)-(31)=0

We add all the numbers together, and all the variables

x*(+10.7/100)-31=0

We multiply parentheses

10x^2-31=0

a = 10; b = 0; c = -31;
Δ = b2-4ac
Δ = 02-4·10·(-31)
Δ = 1240
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:

$\sqrt{\Delta}=\sqrt{1240}=\sqrt{4*310}=\sqrt{4}*\sqrt{310}=2\sqrt{310}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-2\sqrt{310}}{2*10}=\frac{0-2\sqrt{310}}{20}
=-\frac{2\sqrt{310}}{20}
=-\frac{\sqrt{310}}{10}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+2\sqrt{310}}{2*10}=\frac{0+2\sqrt{310}}{20}
=\frac{2\sqrt{310}}{20}
=\frac{\sqrt{310}}{10}
$