d^2+6d-25=0

Solution for d^2+6d-25=0 equation:

d^2+6d-25=0

a = 1; b = 6; c = -25;
Δ = b2-4ac
Δ = 62-4·1·(-25)
Δ = 136
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:

$\sqrt{\Delta}=\sqrt{136}=\sqrt{4*34}=\sqrt{4}*\sqrt{34}=2\sqrt{34}$
$d_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(6)-2\sqrt{34}}{2*1}=\frac{-6-2\sqrt{34}}{2}
$
$d_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(6)+2\sqrt{34}}{2*1}=\frac{-6+2\sqrt{34}}{2}
$