8d*4d-5d-4=3D

Solution for 8d*4d-5d-4=3D equation:

8d*4d-5d-4=3

We move all terms to the left:

8d*4d-5d-4-(3)=0

We add all the numbers together, and all the variables

-5d+8d*4d-7=0

Wy multiply elements

32d^2-5d-7=0

a = 32; b = -5; c = -7;
Δ = b2-4ac
Δ = -52-4·32·(-7)
Δ = 921
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$d_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$d_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$d_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-5)-\sqrt{921}}{2*32}=\frac{5-\sqrt{921}}{64}
$
$d_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-5)+\sqrt{921}}{2*32}=\frac{5+\sqrt{921}}{64}
$