Substitute 2 values for ##x## and solve for ##y## in order to find two points on the line and plot them. Then draw a straight line through them.
##y=-2/5x+2##
Find two points on the line.
Point A:
##x=0##
##y=-2/5*0+2##
##y=0+2##
##y=2##
Point A##=####(02)##
Point B:
##x=5##
##y=-2/5*5+2##
##y=-10/5+2##
##y=-2+2##
##y=0##
Point B##=####(50)##
Plot point A and B then draw a straight line through them.
graph{y=-2/5x+2 [-9.33 10.67 -2.15 7.85]}