To use the substitution method, you first need to set j or k = to something else like this. j+k=3 subtract k from both sides to get j=3-k
Now use the second equation and substitute 3-k where j is like this. 3-k-k=7
3-2k=7 subtract 3 from both sides to get -2k=4
divide both sides by -2 to get k=-2
now use -2 for k and solve for j in either equation and you will get. j=5
