30=3.1x^2

Solution for 30=3.1x^2 equation:

30=3.1x^2

We move all terms to the left:

30-(3.1x^2)=0

We get rid of parentheses

-3.1x^2+30=0

a = -3.1; b = 0; c = +30;
Δ = b2-4ac
Δ = 02-4·(-3.1)·30
Δ = 372
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:

$\sqrt{\Delta}=\sqrt{372}=\sqrt{4*93}=\sqrt{4}*\sqrt{93}=2\sqrt{93}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-2\sqrt{93}}{2*-3.1}=\frac{0-2\sqrt{93}}{-6.2}
=-\frac{2\sqrt{93}}{-6.2}
=-\frac{\sqrt{93}}{-3.1}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+2\sqrt{93}}{2*-3.1}=\frac{0+2\sqrt{93}}{-6.2}
=\frac{2\sqrt{93}}{-6.2}
=\frac{\sqrt{93}}{-3.1}
$