0=x^2-4.5x-9

Solution for 0=x^2-4.5x-9 equation:

0=x^2-4.5x-9

We move all terms to the left:

0-(x^2-4.5x-9)=0

We add all the numbers together, and all the variables

-(x^2-4.5x-9)=0

We get rid of parentheses

-x^2+4.5x+9=0

We add all the numbers together, and all the variables

-1x^2+4.5x+9=0

a = -1; b = 4.5; c = +9;
Δ = b2-4ac
Δ = 4.52-4·(-1)·9
Δ = 56.25
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(4.5)-\sqrt{56.25}}{2*-1}=\frac{-4.5-\sqrt{56.25}}{-2}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(4.5)+\sqrt{56.25}}{2*-1}=\frac{-4.5+\sqrt{56.25}}{-2}
$