McDougal Littell Algebra 2, Chapter 3, 3.2, Section 3.2, Problem 48

Let me try this...
-x+15y=17
-x=-15y+17
x=15y-17
2(15y-17)-10y=-34
2x15y= 30y
2x-17= -34
30y-10y-34=-34
20y=0
y=0
-x+15(0)=17
x=-17

If I got this wrong I apologize.