1. The function y = 7 + 3(x - 2) is linear because it can be written in the form y = mx + b, where m is the slope (3) and b is the y-intercept (7). 2. The data points (1, 12) (2,7) (3,4) (4, 3) (5, 4) define a non-linear relationship because as x increases, y does not increase or decrease at a consistent rate. 3. No information is provided to determine if a third function is linear or non-linear.