0=k^2+9k-135

Solution for 0=k^2+9k-135 equation:

0=k^2+9k-135

We move all terms to the left:

0-(k^2+9k-135)=0

We add all the numbers together, and all the variables

-(k^2+9k-135)=0

We get rid of parentheses

-k^2-9k+135=0

We add all the numbers together, and all the variables

-1k^2-9k+135=0

a = -1; b = -9; c = +135;
Δ = b2-4ac
Δ = -92-4·(-1)·135
Δ = 621
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$k_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$k_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

The end solution:

$\sqrt{\Delta}=\sqrt{621}=\sqrt{9*69}=\sqrt{9}*\sqrt{69}=3\sqrt{69}$
$k_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-9)-3\sqrt{69}}{2*-1}=\frac{9-3\sqrt{69}}{-2}
$
$k_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-9)+3\sqrt{69}}{2*-1}=\frac{9+3\sqrt{69}}{-2}
$