Final answer:
The given equations A, B, and C are all linear equations, as they can be expressed in the form y = mx + b, with a slope (m) and a y-intercept (b).
Step-by-step explanation:
The student's question pertains to the identification of linear equations among a set of given equations. In linear equations, the highest power of the variable(s) is one, and these equations can be written in the slope-intercept form y = mx + b, where m is the slope and b is the y-intercept.
In the referenced Practice Test 4 solutions, it is clarified that Equations A, B, and C are linear because they can all be rewritten in this form. For example, y = -3x (Equation A) is a linear equation with a slope of -3 and a y-intercept of 0. Similarly, Equations B and C can be shown to be linear by simple rearrangement into the slope-intercept form.