0=4w^2-9w-90

Solution for 0=4w^2-9w-90 equation:

0=4w^2-9w-90

We move all terms to the left:

0-(4w^2-9w-90)=0

We add all the numbers together, and all the variables

-(4w^2-9w-90)=0

We get rid of parentheses

-4w^2+9w+90=0

a = -4; b = 9; c = +90;
Δ = b2-4ac
Δ = 92-4·(-4)·90
Δ = 1521
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$w_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$w_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1521}=39$
$w_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(9)-39}{2*-4}=\frac{-48}{-8}
=+6
$
$w_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(9)+39}{2*-4}=\frac{30}{-8}
=-3+3/4
$