Question

If 49x - 57y = 172 ; 57x - 49y = 252 , then x - y = _____ ​

Answer 1

Answer:

ANSWER

49x−57y=172...........(I)

57x−49y=252...........(II)

Adding (I) and (II)

49x+57x−57y−49y=172+252

⇒106x−106y=424

⇒x−y=4...............(III)

Subtracting (II) from (I) we have

49x+57x−57y−(−49y)=252−172

⇒−8x−8y=−80

⇒−x−y=−10

⇒x+y=10...............(IV)

Adding (III) and (IV)

x−y=4

x+y=10

⇒2x=14

⇒x=7

Putting the value of x = 7 in (IV) we get

7+y=10

⇒y=10−7

⇒y=3

Thus, (x,y)=(7,3)