(3x+2)(-5x-2)=0

Solution for (3x+2)(-5x-2)=0 equation:

(3x+2)(-5x-2)=0

We multiply parentheses ..

(-15x^2-6x-10x-4)=0

We get rid of parentheses

-15x^2-6x-10x-4=0

We add all the numbers together, and all the variables

-15x^2-16x-4=0

a = -15; b = -16; c = -4;
Δ = b2-4ac
Δ = -162-4·(-15)·(-4)
Δ = 16
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{16}=4$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-16)-4}{2*-15}=\frac{12}{-30}
=-2/5
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-16)+4}{2*-15}=\frac{20}{-30}
=-2/3
$