(3x+5)(3x-1)=0

Solution for (3x+5)(3x-1)=0 equation:

(3x+5)(3x-1)=0

We multiply parentheses ..

(+9x^2-3x+15x-5)=0

We get rid of parentheses

9x^2-3x+15x-5=0

We add all the numbers together, and all the variables

9x^2+12x-5=0

a = 9; b = 12; c = -5;
Δ = b2-4ac
Δ = 122-4·9·(-5)
Δ = 324
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{324}=18$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(12)-18}{2*9}=\frac{-30}{18}
=-1+2/3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(12)+18}{2*9}=\frac{6}{18}
=1/3
$