(10)*(45-10y)*(y)=18

Solution for (10)*(45-10y)*(y)=18 equation:

(10)(45-10y)(y)=18

We move all terms to the left:

(10)(45-10y)(y)-(18)=0

We add all the numbers together, and all the variables

10(-10y+45)y-18=0

We multiply parentheses

-100y^2+450y-18=0

a = -100; b = 450; c = -18;
Δ = b2-4ac
Δ = 4502-4·(-100)·(-18)
Δ = 195300
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{195300}=\sqrt{900*217}=\sqrt{900}*\sqrt{217}=30\sqrt{217}$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(450)-30\sqrt{217}}{2*-100}=\frac{-450-30\sqrt{217}}{-200}
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(450)+30\sqrt{217}}{2*-100}=\frac{-450+30\sqrt{217}}{-200}
$