Hi a short one, I got everything except this last part.

Show that a unique solution exists for all other k. Find this solution.

I constructed a matrix from the equations

x+2y-2z = 5

x-y+3z =-1

x-7y+k = -k

and found out that there will be infinite no of solutions when k =13

When k is not 13, the system will have a unique solution, but as the question asks, how am I supposed to show? And how do I find the value when they say all other values of k, it doesn't make snese to e because I can't possibly use all values exceept 13..

Thank you very much!