2k^2-25=5k

Solution for 2k^2-25=5k equation:

2k^2-25=5k

We move all terms to the left:

2k^2-25-(5k)=0

a = 2; b = -5; c = -25;
Δ = b2-4ac
Δ = -52-4·2·(-25)
Δ = 225
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$k_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$k_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{225}=15$
$k_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-5)-15}{2*2}=\frac{-10}{4}
=-2+1/2
$
$k_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-5)+15}{2*2}=\frac{20}{4}
=5
$