I am going to solve the problem with changed numbers so you actually do the work:
If the problem was -10x+y=5 instead
Then all we have to do is first switch the graph into standard form (y=mx+b)
y=10x+5
Then Change the slope to its negative reciprocal:
y=(-1/10)x+5
...and you have your slope: -1/10 (This is not your answer)
Now try it with your equation.