900y=y^2

Solution for 900y=y^2 equation:

900y=y^2

We move all terms to the left:

900y-(y^2)=0

determiningTheFunctionDomain
-y^2+900y=0

We add all the numbers together, and all the variables

-1y^2+900y=0

a = -1; b = 900; c = 0;
Δ = b2-4ac
Δ = 9002-4·(-1)·0
Δ = 810000
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{810000}=900$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(900)-900}{2*-1}=\frac{-1800}{-2}
=+900
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(900)+900}{2*-1}=\frac{0}{-2}
=0
$