9k^2-8k-13=4

Solution for 9k^2-8k-13=4 equation:

9k^2-8k-13=4

We move all terms to the left:

9k^2-8k-13-(4)=0

We add all the numbers together, and all the variables

9k^2-8k-17=0

a = 9; b = -8; c = -17;
Δ = b2-4ac
Δ = -82-4·9·(-17)
Δ = 676
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$k_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$k_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{676}=26$
$k_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-8)-26}{2*9}=\frac{-18}{18}
=-1
$
$k_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-8)+26}{2*9}=\frac{34}{18}
=1+8/9
$