y2-781=0

Solution for y2-781=0 equation:

y2-781=0

We add all the numbers together, and all the variables

y^2-781=0

a = 1; b = 0; c = -781;
Δ = b2-4ac
Δ = 02-4·1·(-781)
Δ = 3124
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{3124}=\sqrt{4*781}=\sqrt{4}*\sqrt{781}=2\sqrt{781}$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-2\sqrt{781}}{2*1}=\frac{0-2\sqrt{781}}{2}
=-\frac{2\sqrt{781}}{2}
=-\sqrt{781}
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+2\sqrt{781}}{2*1}=\frac{0+2\sqrt{781}}{2}
=\frac{2\sqrt{781}}{2}
=\sqrt{781}
$