How would you solve a matrix with constants inside of it (such as h,k). An example I was given was

-7x + 3y + 4z = 3

-4x - 4y - 4z = -5

29x -y + h = k

and was told to find "This system has a unique solution whenever

"

What I did was bring the matrix to a form as close as I could to row echelon form, but I have no idea what the conditions are to find what k isnt equal to for a unique solution to be found.

The near row echelon form I found was

x + 11y + 12z = 13

0x + 1y + 11/10z = 47/40

0x + 0y + (9/5 + h)z = k + 67/20

and from there I'm at a complete loss as to how to solve the problem