25=2x^2-10

Solution for 25=2x^2-10 equation:

25=2x^2-10

We move all terms to the left:

25-(2x^2-10)=0

We get rid of parentheses

-2x^2+10+25=0

We add all the numbers together, and all the variables

-2x^2+35=0

a = -2; b = 0; c = +35;
Δ = b2-4ac
Δ = 02-4·(-2)·35
Δ = 280
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:

$\sqrt{\Delta}=\sqrt{280}=\sqrt{4*70}=\sqrt{4}*\sqrt{70}=2\sqrt{70}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-2\sqrt{70}}{2*-2}=\frac{0-2\sqrt{70}}{-4}
=-\frac{2\sqrt{70}}{-4}
=-\frac{\sqrt{70}}{-2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+2\sqrt{70}}{2*-2}=\frac{0+2\sqrt{70}}{-4}
=\frac{2\sqrt{70}}{-4}
=\frac{\sqrt{70}}{-2}
$