Question

Use graph paper for this question. Draw the graph of 2x - y - 1 = 0 and 2x + y = 9 on the same axes. Use 2 cm = 1 unit on both axes and plot only 3 points per line. Write down the coordinates of the point of intersection of the two lines.

Answer 1

2x - y - 1 = 0

⇒ 2x = y + 1

⇒ x = `(y + 1)/(2)`

This table for 2x - y - 1 = 0 is

X	2	1	0
Y	3	1	-1

Also we have

2x + y = 9

⇒ 2x = 9 - y

⇒ x = `(9 - y)/(2)`

The table for 2x + y = 9 is

X	4	3	5
Y	1	3	-1

Plotting the above points we get the following required graph:

From the above graph, it is clear that the two lines 2x - y - 1 = 0 and 2x + y = 9 intersect at the point (2, 5, 4)