**11.2.1 Linear Equations II, PT3 Focus Practice**

Question 1:

Question 1:

It is given that 2

*x*= 6 and 3*x*+*y*= 10.Calculate the value of

*y*.

*Solution:*2

*x*= 6*x*= 3

Substitute

*x*= 3 into 3*x*+*y*= 103 (3) +

*y*= 10*y*= 10 – 9

*y***= 1**

**Question 2:**

It is given that

*y*= –1 and*x*– 3*y*= –10.Calculate the value of

*x*.

*Solution:*Substitute

*y*= –1 into*x*– 3*y*= –10*x*– 3 (–1) = –10

*x*+ 3 = –10

*x*= –10 – 3

*x***= –13**

**Question 3:**

It is given that 7

*x*– 2*y*= 19 and*x*+*y*= 13.Calculate the value of

*y*.

*Solution:*

*Using Substitution method*7

*x*– 2*y*= 19 ——– (1)*x*+

*y*= 13 ——- (2)

From equation (2),

*x*= 13 –

*y*——- (3)

Substitute equation (3) into equation (1),

7

*x*– 2*y*= 197 (13 –

*y*) – 2*y*= 1991 – 7

*y*– 2*y*= 19– 9

*y*= 19 – 91– 9

*y*= –72

*y***= 8**

**Question 4:**

It is given that 2

*x*–*y*= 5 and 3*x*– 2*y*= 8.Calculate the value of

*x*.

*Solution:*

*Using Elimination method*2

*x*–*y*= 5 ——– (1)__3__

*x*– 2*y*= 8 ——- (2)(1) × 2: 4

*x*– 2*y*= 10 -------- (3)__3__

*x*– 2*y*= 8 ------- (2)(3) – (2):

*x*– 0*= 2**x*

**= 2**

**Question 5:**

It is given that

*x*+ 2*y*= 4 and*x*+ 6*y*= –4.Calculate the value of

*x*.

*Solution:*

*Using Elimination method**x*+ 2

*y*= 4 -------- (1)

__x____+ 6__

*y*= –4 ------- (2)(1) × 3: 3

*x*+ 6*y*= 12 -------- (3)

__x____+ 6__

*y*= –4 ------- (2)(3) – (2): 2

*x*= 12 – (–4) 2

*x*= 16

*x*= 8