Question

18. Solve
x + 2y = 9
2x+y =12​

Answer 1

Answer:

x+2y=9

2x+y=12

Therefore, x=5 and y=2

Answer 2

x + 2y = 9..(i)

2x + y = 12..(ii)

Multiplying eqn (i) by 2, we have

2x + 4y = 18

(-) 2x + y = 12

----------------------

3y = -6

y = -6/3

y = -2

putting the value of y in eqn (i), we have

x +2.-2 = 9

x = 9 +4

x = 13

Check:

eqn. (i)

x + 2y = 9

13 + 2.-2 =9

13 - 4 = 9

9 = 9

L. H. S. = R. H. S

Therefore the values of x and y are 13 and -2 respectively.

Okay bye.