d^2-11d=-16.7

Solution for d^2-11d=-16.7 equation:

d^2-11d=-16.7

We move all terms to the left:

d^2-11d-(-16.7)=0

We add all the numbers together, and all the variables

d^2-11d+16.7=0

a = 1; b = -11; c = +16.7;
Δ = b2-4ac
Δ = -112-4·1·16.7
Δ = 54.2
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{-(-11)-\sqrt{54.2}}{2*1}=\frac{11-\sqrt{54.2}}{2}
$
$d_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-11)+\sqrt{54.2}}{2*1}=\frac{11+\sqrt{54.2}}{2}
$