25c2-12=1

Solution for 25c2-12=1 equation:

25c^2-12=1

We move all terms to the left:

25c^2-12-(1)=0

We add all the numbers together, and all the variables

25c^2-13=0

a = 25; b = 0; c = -13;
Δ = b2-4ac
Δ = 02-4·25·(-13)
Δ = 1300
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{1300}=\sqrt{100*13}=\sqrt{100}*\sqrt{13}=10\sqrt{13}$
$c_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-10\sqrt{13}}{2*25}=\frac{0-10\sqrt{13}}{50}
=-\frac{10\sqrt{13}}{50}
=-\frac{\sqrt{13}}{5}
$
$c_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+10\sqrt{13}}{2*25}=\frac{0+10\sqrt{13}}{50}
=\frac{10\sqrt{13}}{50}
=\frac{\sqrt{13}}{5}
$