6.25=2x2

Solution for 6.25=2x2 equation:

6.25=2x^2

We move all terms to the left:

6.25-(2x^2)=0

a = -2; b = 0; c = +6.25;
Δ = b2-4ac
Δ = 02-4·(-2)·6.25
Δ = 50
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:

$\sqrt{\Delta}=\sqrt{50}=\sqrt{25*2}=\sqrt{25}*\sqrt{2}=5\sqrt{2}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-5\sqrt{2}}{2*-2}=\frac{0-5\sqrt{2}}{-4}
=-\frac{5\sqrt{2}}{-4}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+5\sqrt{2}}{2*-2}=\frac{0+5\sqrt{2}}{-4}
=\frac{5\sqrt{2}}{-4}
$