### 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 equationin the form ax by = 0 and indicate the values of aand c.

can also be written as

We need to compare the equationwith 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 equationin the form ax by = 0 and indicate the values of aand c.

can also be written as

We need to compare the equationwith 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 equationin the form ax by = 0 and indicate the values of aand c.

can also be written as

We need to compare the equationwith 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 equationin the form ax by = 0 and indicate the values of aand c.

can also be written as

We need to compare the equationwith 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 equationin the form ax by = 0 and indicate the values of aand c.

can also be written as

We need to compare the equationwith 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 equationin the form ax by = 0 and indicate the values of aand c.

can also be written as

We need to compare the equationwith 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 equationin the form ax by = 0 and indicate the values of aand c.

can also be written as

We need to compare the equationwith 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 equationin the form ax by = 0 and indicate the values of aand c.

can also be written as

We need to compare the equationwith the general equation ax by = 0, to get the values of aand c.

Therefore, we can conclude that.