[tex]\dfrac{K(x^{6})}{x^{6}} = \dfrac{1}{x^{6}}[/tex] where [tex]x \ne 0[/tex]

[tex]K = \dfrac{1}{x^{6}}[/tex]

Actually, here is the original problem:

A die has its six faces loaded so that P(roll is i)=K*x for x=1,2,3,4,5,6. It is rolled until an even number appears. Let X be the number of rolls needed.

Next finding K is needed.