15k^2+35k+25=90

Solution for 15k^2+35k+25=90 equation:

15k^2+35k+25=90

We move all terms to the left:

15k^2+35k+25-(90)=0

We add all the numbers together, and all the variables

15k^2+35k-65=0

a = 15; b = 35; c = -65;
Δ = b2-4ac
Δ = 352-4·15·(-65)
Δ = 5125
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:

$\sqrt{\Delta}=\sqrt{5125}=\sqrt{25*205}=\sqrt{25}*\sqrt{205}=5\sqrt{205}$
$k_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(35)-5\sqrt{205}}{2*15}=\frac{-35-5\sqrt{205}}{30}
$
$k_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(35)+5\sqrt{205}}{2*15}=\frac{-35+5\sqrt{205}}{30}
$