(5x+2)(7x-2)=0

Solution for (5x+2)(7x-2)=0 equation:

(5x+2)(7x-2)=0

We multiply parentheses ..

(+35x^2-10x+14x-4)=0

We get rid of parentheses

35x^2-10x+14x-4=0

We add all the numbers together, and all the variables

35x^2+4x-4=0

a = 35; b = 4; c = -4;
Δ = b2-4ac
Δ = 42-4·35·(-4)
Δ = 576
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{576}=24$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(4)-24}{2*35}=\frac{-28}{70}
=-2/5
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(4)+24}{2*35}=\frac{20}{70}
=2/7
$