Question 18

This question was also unpopular among the candidates.  In solving this problem, it was adviceable to sketch the diagram first showing the points P, Q and R as shown below.

From the diagram, a + c = 4, b + d  =  2,  a + e   =  10,  b + f = 6,  c + e  = 6, d + f = 14.
The solution of these six equations gives Q = (0, 5),   P = (4, - 3)  and  R(6, 9).

The equation of the line PQ is gotten by finding the gradient of PQ thus:
                 5 + 3    =  - 2     
                   - 4
equation of PQ   =   y + 3   =   - 2  »   y + 2x  -  5   =  0
                                   x - 4
                                                       { 0  5   1}
The area of triangle PQR  =   ½  {4 –3  1  }   =   32  square units.
                                                       { 6   9  1}