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

Solution for (1+9y)(1-9y)=0 equation:

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

We add all the numbers together, and all the variables

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

We multiply parentheses ..

(-81y^2+9y-9y+1)=0

We get rid of parentheses

-81y^2+9y-9y+1=0

We add all the numbers together, and all the variables

-81y^2+1=0

a = -81; b = 0; c = +1;
Δ = b2-4ac
Δ = 02-4·(-81)·1
Δ = 324
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{324}=18$
$y_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(0)-18}{2*-81}=\frac{-18}{-162}
=1/9
$
$y_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(0)+18}{2*-81}=\frac{18}{-162}
=-1/9
$