General Mathematics Paper 2,Nov/Dec. 2012
 Questions: 1 2 3 4 5 6 7 8 9 10 11 12 13 Main
Weakness/Remedies
Strengths

Question 9

• Copy and complete the following table of values for the relation y =  + 2x – 2.
 x -4 -3 -2 -1 0 1 2 3 y -3 -2
• Using a scale of 2 cm to 1 unit on both axes, draw the graph of

y =  + 2x – 2 for -4 ≤ x ≤ 2.

• find the roots of the equation  + 2x – 2;
• indicate the region where  + 2x < 0.5.

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Observation

This question was reported to be quite popular with the candidates who were able to complete the table of values and draw the required graph.  However, reading and answering questions from the graph were poorly handled by majority of the candidates.  The expected table of values was:

 x -4 -3 -2 -1 0 1 2 3 y 6 1 -2 -3 -2 1 6 13

These points would then be plotted on a graph sheet using the given scale.  The roots of the equation  + 2x = 2 were the points of intersection of the graph and the x - axis which were at x = -2.7 ± 0.1 and 0.75  ±  0.01.  The required region was the region where y  <  -1.5.  They were obtained from the graph as -2.2 ± 0.1 < x < 0.2 ± 0.1.  Candidates could either state this interval or shade the area on their graph.