(50-y)*y=621

Solution for (50-y)*y=621 equation:

(50-y)*y=621

We move all terms to the left:

(50-y)*y-(621)=0

We add all the numbers together, and all the variables

(-1y+50)*y-621=0

We multiply parentheses

-1y^2+50y-621=0

a = -1; b = 50; c = -621;
Δ = b2-4ac
Δ = 502-4·(-1)·(-621)
Δ = 16
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{16}=4$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(50)-4}{2*-1}=\frac{-54}{-2}
=+27
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(50)+4}{2*-1}=\frac{-46}{-2}
=+23
$