(8x+7)(15x+10)=0

Solution for (8x+7)(15x+10)=0 equation:

(8x+7)(15x+10)=0

We multiply parentheses ..

(+120x^2+80x+105x+70)=0

We get rid of parentheses

120x^2+80x+105x+70=0

We add all the numbers together, and all the variables

120x^2+185x+70=0

a = 120; b = 185; c = +70;
Δ = b2-4ac
Δ = 1852-4·120·70
Δ = 625
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{625}=25$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(185)-25}{2*120}=\frac{-210}{240}
=-7/8
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(185)+25}{2*120}=\frac{-160}{240}
=-2/3
$