5d2+10d-9=0

Solution for 5d2+10d-9=0 equation:

5d^2+10d-9=0

a = 5; b = 10; c = -9;
Δ = b2-4ac
Δ = 102-4·5·(-9)
Δ = 280
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$d_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$d_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{280}=\sqrt{4*70}=\sqrt{4}*\sqrt{70}=2\sqrt{70}$
$d_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(10)-2\sqrt{70}}{2*5}=\frac{-10-2\sqrt{70}}{10}
$
$d_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(10)+2\sqrt{70}}{2*5}=\frac{-10+2\sqrt{70}}{10}
$