## Chapter 8 Linear Equations in Two Variables Ex 8.1

**Question 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 ₹ x and that of a pen to be ₹ y)**
**Solution:**

Let the cost of a notebook = ₹ x

and the cost of a pen = ₹ y

According to question,

Cost of a notebook = 2(cost of a pen)

∴ x = 2y

⇒ x- 2y = 0

**(iii)** – 2x+ 3y = 6

⇒ -2x + 3y – 6=0

On comparing with ax + by + c = 0, then the values of a = – 2, b = 3 and c = – 6

**(iv)** x = 3y ⇒ x-3y+0=0

On comparing with ax + by + c = 0, then the values of a = 1, b = – 3 and c = 0.

**(v)** 2x = -5y

⇒ 2x + 5y + 0=0

On comparing with ax + by + c = 0, then the values of a = 2, b = 5 and c = 0.

**(vi)** 3x + 2 = 0

⇒ 3x + 0y + 2 = 0

On comparing with ax + by + c = 0, then the values of a = 3, b = 0 and , c= 2.

**(vii)** y – 2 = 0

⇒0x+y-2 = 0

On comparing with ax + by + c = 0, then the values of a = 0, b = 1 and c = – 2.

**(viii)** 5 = 2x ⇒ 2x + 0y – 5 = 0

On comparing with ax + by + c = 0, then the values of a = 2, b = 0 and c = – 5.