D(x)=-4x2-9x-4

Solution for D(x)=-4x2-9x-4 equation:

(D)=-4D^2-9D-4

We move all terms to the left:

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

We get rid of parentheses

4D^2+9D+D+4=0

We add all the numbers together, and all the variables

4D^2+10D+4=0

a = 4; b = 10; c = +4;
Δ = b2-4ac
Δ = 102-4·4·4
Δ = 36
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$D_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$D_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{36}=6$
$D_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(10)-6}{2*4}=\frac{-16}{8}
=-2
$
$D_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(10)+6}{2*4}=\frac{-4}{8}
=-1/2
$