Question

49x-57y=172 101x+99y=501
$49x - 57y = 172 \: \: 57x - 49y = 252$

Answer 1

put the x together,change signs,calculate
put the y together,change signs,calculate

Answer 2

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-57y-57y-(-49y)=252-172

⇒-8x-8y=-80

⇒-x-y=-10

⇒x+y=10 .....(IV)

Adding (III) and (IV)

x-y=4x+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).