Question

EXERCISE 4.3
1. Draw the graph of each of the following linear equations in two variables:
(1) x+y=4 (ü) r- y=2 (iii) y=3x
(iv) 3 = 2x + y​

Answer 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. x and that of a pen to be Rs. y).

Sol: Let the cost of a notebook = Rs x

The cost of a pen = y

According to the condition, we have

[Cost of a notebook] = 2 × [Cost of a pen]

i.e. [x] = 2 × [Y]

or x = 2y

or x – 2y = 0

Thus, the required linear equation is × – 2y = 0.