1) (a) Variables x and y are related by the equation y= 5x+2
i) Find the approximate change in y when x increases from 0 to p, where p is small.
(b) A square of area A cm
2 has a side of length x cm. Given that the area is increasing at a constant rate of 0.5cm
2s
-1. Find the rate of increase of x when A =9.
Help, please