-112=2x^2-30x

Solution for -112=2x^2-30x equation:

-112=2x^2-30x

We move all terms to the left:

-112-(2x^2-30x)=0

We get rid of parentheses

-2x^2+30x-112=0

a = -2; b = 30; c = -112;
Δ = b2-4ac
Δ = 302-4·(-2)·(-112)
Δ = 4
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{4}=2$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(30)-2}{2*-2}=\frac{-32}{-4}
=+8
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(30)+2}{2*-2}=\frac{-28}{-4}
=+7
$