4y^2-20y-144=0

Solution for 4y^2-20y-144=0 equation:

4y^2-20y-144=0

a = 4; b = -20; c = -144;
Δ = b2-4ac
Δ = -202-4·4·(-144)
Δ = 2704
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2704}=52$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-20)-52}{2*4}=\frac{-32}{8}
=-4
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-20)+52}{2*4}=\frac{72}{8}
=9
$