(19-y)*y=40

Solution for (19-y)*y=40 equation:

(19-y)*y=40

We move all terms to the left:

(19-y)*y-(40)=0

We add all the numbers together, and all the variables

(-1y+19)*y-40=0

We multiply parentheses

-1y^2+19y-40=0

a = -1; b = 19; c = -40;
Δ = b2-4ac
Δ = 192-4·(-1)·(-40)
Δ = 201
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(19)-\sqrt{201}}{2*-1}=\frac{-19-\sqrt{201}}{-2}
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(19)+\sqrt{201}}{2*-1}=\frac{-19+\sqrt{201}}{-2}
$