Is 5x=y-4 a linear equation

Suppose that the price p (in dollars) and the weekly sales x (in thousands of units) of a certain commodity satisfy the demand equation 4p cubedplusx squaredequals38 comma 400. determine the rate at which sales are changing at a time when xequals80, pequals20, and the price is falling at the rate of $.20 per week.

Write two point-slope equations for the line passing through the points (6, 5) and (3, 1)

Out of 50 students surveyed, 16 have a dog. based on these results, predict how many of the 280 students in the school have a dog.