750-y(y-5)=0

Solution for 750-y(y-5)=0 equation:

750-y(y-5)=0

We multiply parentheses

-y^2+5y+750=0

We add all the numbers together, and all the variables

-1y^2+5y+750=0

a = -1; b = 5; c = +750;
Δ = b2-4ac
Δ = 52-4·(-1)·750
Δ = 3025
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{3025}=55$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(5)-55}{2*-1}=\frac{-60}{-2}
=+30
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(5)+55}{2*-1}=\frac{50}{-2}
=-25
$