(5x+2)*(15x+2)=0

Solution for (5x+2)*(15x+2)=0 equation:

(5x+2)(15x+2)=0

We multiply parentheses ..

(+75x^2+10x+30x+4)=0

We get rid of parentheses

75x^2+10x+30x+4=0

We add all the numbers together, and all the variables

75x^2+40x+4=0

a = 75; b = 40; c = +4;
Δ = b2-4ac
Δ = 402-4·75·4
Δ = 400
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{400}=20$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(40)-20}{2*75}=\frac{-60}{150}
=-2/5
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(40)+20}{2*75}=\frac{-20}{150}
=-2/15
$