###### Practice Set 1.4

Question 1.Solve the following simultaneous equation.

Answer:

Let = m and = n

Multiply Eq. I by 4

Equating Eq. II and III. Change the signs of Eq. III

Substituting n=1 in Eq. II

∴ ⇒ ⇒

∴ ⇒ ⇒

Hence (x,y) = (

Question 2.

Solve the following simultaneous equation.

Answer:

Let = m and = n

Multiply Eq. I by 5 and Eq.II by 2

Substituting in Eq. I

∴ ⇒ ⇒ ….(III)

∴ ⇒ ⇒ ….(IV)

Now, equating Eq. III and IV

Subsituting value of x=3 in Eq. III

Hence (x,y) = (

Question 3.

Solve the following simultaneous equation.

Answer:

Let = m and = n

Adding both equations

Dividing both sides by 58

…(III)

Subtracting Eq. I and II

Dividing both sides by 4

…(IV)

Equating Eq. III and IV

Subsituting n=1 in Eq. III

∴ ⇒ ⇒ ⇒ ⇒

⇒ ⇒

∴ ⇒ ⇒ ⇒ ⇒

Hence (x,y) = (

Question 4.

Solve the following simultaneous equation.

Answer:

Let = m and = n

⇒

⇒

Multiply Eq. I by 2

.... (a)

..... (b)

Add (a) and (b) to get,8m + 8n + 8m - 8n = 8

⇒ 16m = 8

Substituting in Eq. II

⇒ 4 - 8n = 2

⇒ - 8n = 2 - 4

⇒ - 8n = -2

⇒

⇒

∴

⇒

⇒ 2 = 2 (3x+y)

⇒ 2 = 6x + 2y ...... III

∴

⇒

⇒ 4 = 2(3x - y)

⇒ 4 = 6x - 2y ….IV

Add Eq. III and IV

Substituting

⇒ 3 + 2y = 2

⇒ 2y = 2 - 3

⇒ 2y = -1

Hence (x,y) = (