-10=30x-x^2

Solution for -10=30x-x^2 equation:

-10=30x-x^2

We move all terms to the left:

-10-(30x-x^2)=0

We get rid of parentheses

x^2-30x-10=0

a = 1; b = -30; c = -10;
Δ = b2-4ac
Δ = -302-4·1·(-10)
Δ = 940
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:

$\sqrt{\Delta}=\sqrt{940}=\sqrt{4*235}=\sqrt{4}*\sqrt{235}=2\sqrt{235}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-30)-2\sqrt{235}}{2*1}=\frac{30-2\sqrt{235}}{2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-30)+2\sqrt{235}}{2*1}=\frac{30+2\sqrt{235}}{2}
$