-4y*5y=-180

Solution for -4y*5y=-180 equation:

-4y*5y=-180

We move all terms to the left:

-4y*5y-(-180)=0

We add all the numbers together, and all the variables

-4y*5y+180=0

Wy multiply elements

-20y^2+180=0

a = -20; b = 0; c = +180;
Δ = b2-4ac
Δ = 02-4·(-20)·180
Δ = 14400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{14400}=120$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-120}{2*-20}=\frac{-120}{-40}
=+3
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+120}{2*-20}=\frac{120}{-40}
=-3
$