26y^2-8y-64=0

Solution for 26y^2-8y-64=0 equation:

26y^2-8y-64=0

a = 26; b = -8; c = -64;
Δ = b2-4ac
Δ = -82-4·26·(-64)
Δ = 6720
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:

$\sqrt{\Delta}=\sqrt{6720}=\sqrt{64*105}=\sqrt{64}*\sqrt{105}=8\sqrt{105}$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-8)-8\sqrt{105}}{2*26}=\frac{8-8\sqrt{105}}{52}
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-8)+8\sqrt{105}}{2*26}=\frac{8+8\sqrt{105}}{52}
$