0=4x^2-4x-9

Solution for 0=4x^2-4x-9 equation:

0=4x^2-4x-9

We move all terms to the left:

0-(4x^2-4x-9)=0

We add all the numbers together, and all the variables

-(4x^2-4x-9)=0

We get rid of parentheses

-4x^2+4x+9=0

a = -4; b = 4; c = +9;
Δ = b2-4ac
Δ = 42-4·(-4)·9
Δ = 160
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{160}=\sqrt{16*10}=\sqrt{16}*\sqrt{10}=4\sqrt{10}$
$x_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(4)-4\sqrt{10}}{2*-4}=\frac{-4-4\sqrt{10}}{-8}
$
$x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(4)+4\sqrt{10}}{2*-4}=\frac{-4+4\sqrt{10}}{-8}
$