5(7-3x)(5x+1)=0

Solution for 5(7-3x)(5x+1)=0 equation:

5(7-3x)(5x+1)=0

We add all the numbers together, and all the variables

5(-3x+7)(5x+1)=0

We multiply parentheses ..

5(-15x^2-3x+35x+7)=0

We multiply parentheses

-75x^2-15x+175x+35=0

We add all the numbers together, and all the variables

-75x^2+160x+35=0

a = -75; b = 160; c = +35;
Δ = b2-4ac
Δ = 1602-4·(-75)·35
Δ = 36100
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{36100}=190$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(160)-190}{2*-75}=\frac{-350}{-150}
=2+1/3
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(160)+190}{2*-75}=\frac{30}{-150}
=-1/5
$