Find the y-intercept (7 because it's in slope-intercept form). That would be (0,7). Plot that point.
Find another point. For example, plug in 1 for x. Then solve for f(x) which would be -3(1) + 7 = 4. That would be (1, 4). Plot that point.
Connect the dots and you have a line.
The domain is (-infinity, infinity) because it's an infinite line.
The range is the same because it's an infinite line.
6/100+11/100+19/100= 36/100. 36/100 in simplest form is 9/25