Question

Function 1: y = 4x + 5

Answer 1

Answer: function 1

Rate of change of function 1:
Following the format of y=mx+c, the rate of change should be m, so, the rate of change for function 1 = 4

To find the gradient (rate of change):
The two points the line passes through are (x1, y1) and (x2, y2), which in this case is (1, 6) and (3, 10)
(Doesn't matter which is which but you need to make sure that once you decide which is which, you stick to it)
To calculate the gradient, you substitute these values following (y1 - y2)/(x1 - x2)

Gradient of function 2 = (10 - 6)/(3 - 1)
= 2

Therefore, since 4 > 2, rate of change of function 1 > rate of change of function 2.