9y(y=1)-9y=45

Solution for 9y(y=1)-9y=45 equation:

9y(y=1)-9y=45

We move all terms to the left:

9y(y-(1)-9y)=0

We add all the numbers together, and all the variables

9y(-8y-1)=0

We multiply parentheses

-72y^2-9y=0

a = -72; b = -9; c = 0;
Δ = b2-4ac
Δ = -92-4·(-72)·0
Δ = 81
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{81}=9$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-9)-9}{2*-72}=\frac{0}{-144}
=0
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-9)+9}{2*-72}=\frac{18}{-144}
=-1/8
$