4/3d= 12?

and

3/4k - 1 = 1/3k?

:)

on the second subtract 1/3 k from each side. Then add 1 to each side.

3/4 k-1/3= 1
k(9/12 -4/13_=1
and proceed from there.
5/12 k=1
multiply each side by 12
divide each side by 2