Question

Draw the graph of equation 2x - y + 1 = 0, using the graph. Find the value of y, when x = -2. [4 MARKS]

Answer 1

Concept: 1 Mark
Graphs: 3 Marks

2x - y + 1 = 0
y = 2x + 1

$\begin{array}{cccc}x& 0& 1& 2\\ y& 1& 3& 5\\ (x,y)& (0,1)& (1,3)& (2,5)\end{array}$

When x = 0, then
$y=2\times 0+1=1$
When x = 1, then
$y=2\times 1+1=3$
When x = 2, then
$y=2\times 2+1=5$

Now, plot the points A(0, 1), B(1, 3) and C(2, 5) on a graph paper. Draw a line passing through points A, B and C.

Then, the line AB is the required graph of 2x - y + 1 = 0.



When x = -2, y = -3.