Find conditions on k that will make the following system of equations have a unique solution. To enter your answer, first select whether k should be equal or not equal to specific values, then enter a value or a list of values separated by commas.

Then give a formula in terms of k for the solution to the system, when it exists. Be sure to include parentheses where necessary, e.g. to distinguish 1/(2k) from 1/2k.

kx+y = 4
75x+3ky = 3