(9x-45)(-2x-8)=0

Solution for (9x-45)(-2x-8)=0 equation:

(9x-45)(-2x-8)=0

We multiply parentheses ..

(-18x^2-72x+90x+360)=0

We get rid of parentheses

-18x^2-72x+90x+360=0

We add all the numbers together, and all the variables

-18x^2+18x+360=0

a = -18; b = 18; c = +360;
Δ = b2-4ac
Δ = 182-4·(-18)·360
Δ = 26244
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{26244}=162$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(18)-162}{2*-18}=\frac{-180}{-36}
=+5
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(18)+162}{2*-18}=\frac{144}{-36}
=-4
$