(9-w)(5w+8)=0

Solution for (9-w)(5w+8)=0 equation:

(9-w)(5w+8)=0

We add all the numbers together, and all the variables

(-1w+9)(5w+8)=0

We multiply parentheses ..

(-5w^2-8w+45w+72)=0

We get rid of parentheses

-5w^2-8w+45w+72=0

We add all the numbers together, and all the variables

-5w^2+37w+72=0

a = -5; b = 37; c = +72;
Δ = b2-4ac
Δ = 372-4·(-5)·72
Δ = 2809
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$w_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$w_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{2809}=53$
$w_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(37)-53}{2*-5}=\frac{-90}{-10}
=+9
$
$w_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(37)+53}{2*-5}=\frac{16}{-10}
=-1+3/5
$