12.5=2x^2

Solution for 12.5=2x^2 equation:

12.5=2x^2

We move all terms to the left:

12.5-(2x^2)=0

a = -2; b = 0; c = +12.5;
Δ = b2-4ac
Δ = 02-4·(-2)·12.5
Δ = 100
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{100}=10$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-10}{2*-2}=\frac{-10}{-4}
=2+1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+10}{2*-2}=\frac{10}{-4}
=-2+1/2
$