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

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

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

We multiply parentheses ..

(+2x^2-7x+18x-63)=0

We get rid of parentheses

2x^2-7x+18x-63=0

We add all the numbers together, and all the variables

2x^2+11x-63=0

a = 2; b = 11; c = -63;
Δ = b2-4ac
Δ = 112-4·2·(-63)
Δ = 625
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{625}=25$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(11)-25}{2*2}=\frac{-36}{4}
=-9
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(11)+25}{2*2}=\frac{14}{4}
=3+1/2
$