q2-6q-9=0

Solution for q2-6q-9=0 equation:

q2-6q-9=0

We add all the numbers together, and all the variables

q^2-6q-9=0

a = 1; b = -6; c = -9;
Δ = b2-4ac
Δ = -62-4·1·(-9)
Δ = 72
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$q_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$q_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{72}=\sqrt{36*2}=\sqrt{36}*\sqrt{2}=6\sqrt{2}$
$q_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-6)-6\sqrt{2}}{2*1}=\frac{6-6\sqrt{2}}{2}
$
$q_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-6)+6\sqrt{2}}{2*1}=\frac{6+6\sqrt{2}}{2}
$