K = 1.2 Short answer. It's going to seem odd, but one of the ways you could solve this is by multiplying the first equation by 4. I'll tell you why in a moment.
4(0.3x - 0.7y = 1) Now remove the brackets.
1.2x - 2.8y = 4 If you want there to be no solution, the way to do it is the make k = 1.2 The second equation becomes. 1.2x - 2.8y = 3
I'm going to give you the graph of this so you will see why there is no solution. Do you see why?