First you graph..
Start at (5,20)
Count 6 up 1 to the right three or four times then Count 6 down and 1 to the left.
You will get the y-intercept out of this...
Which is -10.
You can put it into slope-intercept form now-
y=mx+b
"m" being slope and "b" being the y-intercept.
Final Answer: y=6x+10