The linear function in slope-intercept form: y = ax + b.
We have y = 3x - 2. It's a linear function. The graph is a straight line. Therefore we need only two points to plotting the graph. Choose two values of x and calculate the values of y:
for x = 0 → y = 3(0) - 2 = 0 - 2 = -2 → (0, -2)
for x = 1 → y= 3(1) - 2 = 3 - 2 = 1 → (1, 1)