The cost of a visit by an electrician is given by this function: y = 25x + 40

• y is the total cost in dollars

• x is the number of hours

• there is a fixed charge and a charge per hour a Copy and complete this table for the function.

b Use the table to plot a graph of y = 25x + 40 Use a scale of 2 cm to 1 unit on the x-axis and 2 cm to 50 units on the y-axis.
c Find the y-intercept and the gradient of the graph.
d What do the y-intercept and the gradient show about the electrician’s charges?

.r 0 1 2 3 4 y