25x2=0.64

Solution for 25x2=0.64 equation:

25x^2=0.64

We move all terms to the left:

25x^2-(0.64)=0

We add all the numbers together, and all the variables

25x^2-0.64=0

a = 25; b = 0; c = -0.64;
Δ = b2-4ac
Δ = 02-4·25·(-0.64)
Δ = 64
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{64}=8$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-8}{2*25}=\frac{-8}{50}
=-4/25
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+8}{2*25}=\frac{8}{50}
=4/25
$