Graph y=−4/7x+1 . Use the line tool and select two points on the line.

Find two points by giving x an y values and solving the equation:
y = -4/7x +1
1 = -4/7x +1, x =0
First point is (0,1)
5 = -4/7x +1, x = -7
Second point is (-7,5)
Now plot those two points on the graph and draw a line through them
See attached picture: