7k^2-25=30k

Solution for 7k^2-25=30k equation:

7k^2-25=30k

We move all terms to the left:

7k^2-25-(30k)=0

a = 7; b = -30; c = -25;
Δ = b2-4ac
Δ = -302-4·7·(-25)
Δ = 1600
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$k_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$k_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$\sqrt{\Delta}=\sqrt{1600}=40$
$k_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(-30)-40}{2*7}=\frac{-10}{14}
=-5/7
$
$k_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(-30)+40}{2*7}=\frac{70}{14}
=5
$