Question 1084224
The two graphs have different slopes, one negative, one positive
They both go through +1, and that occurs when x=0, so (0, 1) is a point for both.
Two other points.
use x=1 and -1
for 3x+1, the points are 4 and -2, so (1, 4) and (-1, -2) are on the line.
for -3x+1, the points are -2 and 4, so (1, -2) and (-1, 4) are on the line.
{{{graph(300,300,-10,10,-10,10,3x+1,-3x+1)}}}