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

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

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

We add all the numbers together, and all the variables

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

We multiply parentheses ..

(+35x^2-25x+14x-10)=0

We get rid of parentheses

35x^2-25x+14x-10=0

We add all the numbers together, and all the variables

35x^2-11x-10=0

a = 35; b = -11; c = -10;
Δ = b2-4ac
Δ = -112-4·35·(-10)
Δ = 1521
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1521}=39$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-11)-39}{2*35}=\frac{-28}{70}
=-2/5
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-11)+39}{2*35}=\frac{50}{70}
=5/7
$