### Linear Equations in Two Variables - Solutions

CBSE Class 9 Mathematics

NCERT Solutions
CHAPTER 4
Linear Equations in Two Variables
(Ex. 4.1)

1. The cost of a notebook is twice the cost of a pen. Write a linear equation in two variables to represent this statement.

(Take the cost of a notebook to be Rs and that of a pen to be Rs y).

Ans. Let the cost of a notebook be .

Let the cost of a pen be .

We need to write a linear equation in two variables to represent the statement, “Cost of a notebook is twice the cost of a pen”.

Therefore, we can conclude that the required statement will be = x -2y = 0

2. Express the following linear equations in the form ax by = 0 and indicate the values of aand in each case:

(i) (ii) (iii) (iv) (v) (vi) (vii) (viii) Ans. (i) We need to express the linear equation in the form ax by = 0 and indicate the values of aand c. can also be written as We need to compare the equation with the general equation ax by = 0, to get the values of aand c.

Therefore, we can conclude that .

(ii) We need to express the linear equation in the form ax by = 0 and indicate the values of aand c. can also be written as We need to compare the equation with the general equation ax by = 0, to get the values of aand c.

Therefore, we can conclude that .

(iii) We need to express the linear equation in the form ax by = 0 and indicate the values of aand c. can also be written as We need to compare the equation with the general equation ax by = 0, to get the values of aand c.

Therefore, we can conclude that .

(iv) We need to express the linear equation in the form ax by = 0 and indicate the values of aand c. can also be written as We need to compare the equation with the general equation ax by = 0, to get the values of aand c.

Therefore, we can conclude that .

(v) We need to express the linear equation in the form ax by = 0 and indicate the values of aand c. can also be written as We need to compare the equation with the general equation ax by = 0, to get the values of aand c.

Therefore, we can conclude that .

(vi) We need to express the linear equation in the form ax by = 0 and indicate the values of aand c. can also be written as We need to compare the equation with the general equation ax by = 0, to get the values of aand c.

Therefore, we can conclude that .

(vii) We need to express the linear equation in the form ax by = 0 and indicate the values of aand c. can also be written as We need to compare the equation with the general equation ax by = 0, to get the values of aand c.

Therefore, we can conclude that .

(viii) We need to express the linear equation in the form ax by = 0 and indicate the values of aand c. can also be written as We need to compare the equation with the general equation ax by = 0, to get the values of aand c.

Therefore, we can conclude that .