1. 
(a) Find the length between the two points A (2, 3) and B (1, 5). 

(b) Find the gradient of the line passing through the two points P (1, 2) and Q (2, 4). 

Hence, find the equation of line PQ. 

2.  A straight line passes through three points
A(1, 3), B(4, 1) and C(3, h) as shown 

in the diagram below. 

Find 

(a) the equation of line AB, 

(b) the value of h. 
