I’ll be assuming you meant k as in
the a in a quadratic equation:
ax^2 + bx + c
kx^2 + bx + c.
In this case, the “k” will indicate whether the graph will be opening upwards to form a “u” shape or it opens downwards to form a “n” shape
When “k” is positive, the graph would open upwards and form a “u”.
If “k” is negative, the graph would open downwards and form a “n”.
Have a great day ahead!