(14x+9)(5x-7)=0

Solution for (14x+9)(5x-7)=0 equation:

(14x+9)(5x-7)=0

We multiply parentheses ..

(+70x^2-98x+45x-63)=0

We get rid of parentheses

70x^2-98x+45x-63=0

We add all the numbers together, and all the variables

70x^2-53x-63=0

a = 70; b = -53; c = -63;
Δ = b2-4ac
Δ = -532-4·70·(-63)
Δ = 20449
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{20449}=143$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-53)-143}{2*70}=\frac{-90}{140}
=-9/14
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-53)+143}{2*70}=\frac{196}{140}
=1+2/5
$