Final answer:
All the provided options are linear equations in the form y = mx + b, where m is the slope and b is the y-intercept. They each represent a straight line with different slopes and y-intercepts.
Step-by-step explanation:
The equation of a line in the slope-intercept form is given by y = mx + b, where m represents the slope of the line, and b represents the y-intercept, the point where the line crosses the y-axis. Based on the provided options, all are linear equations because they follow the form of y = mx + b. For example, option a) y = 2x + 2 is a linear equation where the slope is 2 and the y-intercept is 2. Similarly, option b) y = x - 4, option c) y = -x + 2, and option d) y = 2x - 4 are all linear equations, each with their respective slopes and y-intercepts.