Question

Solve the following pair of linear equation by the substitution method 1) x+y=14 , x-y=4​

Answer 1

x = 9, y = 5  

Step-by-step explanation:

Correct option is

D

None of these

x+y=14 ...(i)

x−y=4 ....(ii)

From (ii) y=x−4 ..(iii)

Substituting y from (iii) in (i), we get

x+x−4=14

⇒2x=18

⇒x=9

Substituting x=9 in (iii), we get

y=9−4=5,

i.e, y=5

x=9,y=5

Answer 2

Answer:

x + y = 14 ---> (i)

x - y = 4 ---> (ii)

Method 1 :

By Elimination method :-

Adding (i) and (ii)

x + y = 14

x - y = 4

__________

2x = 18

=> x = 18/2

=> x = 9

Putting the value of x in (i)

x + y = 14

=> 9 + y = 14

=> y = 14 - 9

=> y = 5

x = 9, y = 5

Method 2 :

By Substitution method :-

x + y = 14

=> x = 14 - y

Putting the value of x in (ii)

x - y = 4

=> 14 - y - y = 4

=> - 2y = 4 - 14

=> - 2y - 10

=> 2y = 10 (Both side minus cancelled)

=> y = 10/2

=> y = 5

Putting the value of y in (i)

x + y = 14

=> x + 5 = 14

=> x = 14 - 5

=> x = 9

x = 9, y = 5

Ans. x = 9, y = 5

Step-by-step explanation:

Here I have given two methods :

i) Elimination method.

ii) Substitution method.

You can do any one of this.

Hope it helps.