81^2-25y^2=0

Solution for 81^2-25y^2=0 equation:

81^2-25y^2=0

We add all the numbers together, and all the variables

-25y^2+6561=0

a = -25; b = 0; c = +6561;
Δ = b2-4ac
Δ = 02-4·(-25)·6561
Δ = 656100
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{656100}=810$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-810}{2*-25}=\frac{-810}{-50}
=16+1/5
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+810}{2*-25}=\frac{810}{-50}
=-16+1/5
$