Lab Manual: Graph of Linear Equation | Lab Manuals for Class 9 PDF Download

Objective

Prerequisite Knowledge
(i) Concept of linear equation.
(ii) To represent the co-ordinates on cartesian plane.

Materials Required
Graph paper, pens, pencil, eraser, ruler.

Procedure

• Construct a linear equation in two variables.
• Let the number of pencils be xand number of pens be y.
• According to the given situation, 60 = 2x + 4y.
• Now we have to represent this situation on the graph paper.
• By taking different values of x we get different values of y. Put different values of x given in table to get corresponding values y as shown.
  
• Take a graph paper and a cartesian system is drawn, i.e., x-axis and y-axis are drawn.
• Plot the coordinates from the above table on the graph and name them as A(0,15), B(2,14), C(4,13), D(6,12).
• On joining the points A, B, C and D we get a straight line.

Fig. (i)

Observation

• We get a straight line, which represents the linear equation [fig. (i)].
• On the line there are infinitely many coordinates. But, according to the situation we have taken those points or coordinates which are natural numbers.

Result

We observed that for the given equation, we get a straight line on the graph paper which cuts the x-axis and y-axis.

Learning Outcome
We learnt that for any one degree equation whether in one variable or two variables, yye will get a straight line on the graph papers. For x = a, line is parallel to y-axis at a distance of a unit from origin. For y = b, line will be parallel to x-axis at a distance of b unit from origin.

Activity Time
For the other daily life situations students can draw linear equation on the graph.

e.g. (i) x=2y (cost of one apple is equal to cost of two oranges).
(ii) x + y = 7 (sum of number of pencils and erasers is 7).