Question

Draw the graph of the equation x + 2y – 3 = 0.
From your graph, find the value of y when
(i) x = 5
(ii) x = –5.

Answer 1

Given equation: x + 2y - 3 = 0
Or, x + 2y = 3
When y = 0, x + 0 = 3 ⇒ x = 3
When y = 1, x + 2 = 3 ⇒ x = 3-2 = 1
When y = 2, x + 4 = 3 ⇒ x = 3 - 4 = -1
Thus, we have the following table:

x	3	1	-1
y	0	1	2

Now plot the points (3,0) ,(1,1) and (-1,2) on the graph paper.
Join the points and extend the line in both the directions.
The line segment is the required graph of the equation.



When x = 5,

$$\begin{gathered} y=\frac{3-x}{2} \\ \Rightarrow y=\frac{3-5}{2} \\ \Rightarrow y=-1 \end{gathered}$$

Similarly, from the graph we can see that when x = −5, y = 4.