5(7x-5)(4x+3)=0

Solution for 5(7x-5)(4x+3)=0 equation:

5(7x-5)(4x+3)=0

We multiply parentheses ..

5(+28x^2+21x-20x-15)=0

We multiply parentheses

140x^2+105x-100x-75=0

We add all the numbers together, and all the variables

140x^2+5x-75=0

a = 140; b = 5; c = -75;
Δ = b2-4ac
Δ = 52-4·140·(-75)
Δ = 42025
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{42025}=205$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(5)-205}{2*140}=\frac{-210}{280}
=-3/4
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(5)+205}{2*140}=\frac{200}{280}
=5/7
$