(x+13)(5x+30)=0

Solution for (x+13)(5x+30)=0 equation:

(x+13)(5x+30)=0

We multiply parentheses ..

(+5x^2+30x+65x+390)=0

We get rid of parentheses

5x^2+30x+65x+390=0

We add all the numbers together, and all the variables

5x^2+95x+390=0

a = 5; b = 95; c = +390;
Δ = b2-4ac
Δ = 952-4·5·390
Δ = 1225
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1225}=35$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(95)-35}{2*5}=\frac{-130}{10}
=-13
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(95)+35}{2*5}=\frac{-60}{10}
=-6
$