(2x-7)(-7x-9)=0

Solution for (2x-7)(-7x-9)=0 equation:

(2x-7)(-7x-9)=0

We multiply parentheses ..

(-14x^2-18x+49x+63)=0

We get rid of parentheses

-14x^2-18x+49x+63=0

We add all the numbers together, and all the variables

-14x^2+31x+63=0

a = -14; b = 31; c = +63;
Δ = b2-4ac
Δ = 312-4·(-14)·63
Δ = 4489
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{4489}=67$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(31)-67}{2*-14}=\frac{-98}{-28}
=3+1/2
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(31)+67}{2*-14}=\frac{36}{-28}
=-1+2/7
$