Using substitution or elimination?
1. multiply the first or second equation by a number that will make one variable 0
For example; if you multiply the bottom equation by “-3”, it will be “-15j-12k=-18”
2. add the two equations together
It will be 15j-15j which equals 0. Additionally, 12k-12k=0. And, 18-18=0
This means that you have 0=0. When this happens, you have infinitely many solutions. Your teacher may only want you to put infinitely many, or they may want you to solve in terms of one of the variables. If it is the latter, let me know and I will help with that.