8+14d=15d^2

Solution for 8+14d=15d^2 equation:

8+14d=15d^2

We move all terms to the left:

8+14d-(15d^2)=0

determiningTheFunctionDomain
-15d^2+14d+8=0

a = -15; b = 14; c = +8;
Δ = b2-4ac
Δ = 142-4·(-15)·8
Δ = 676
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$d_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$d_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{676}=26$
$d_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(14)-26}{2*-15}=\frac{-40}{-30}
=1+1/3
$
$d_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(14)+26}{2*-15}=\frac{12}{-30}
=-2/5
$