Question

10/x+y + 2/x-y= 4 15/x+y-5/x-y =-2 Solve the following bv pair of linear equations by 3 of algebraic methods

Answer 1

10/x+y +2/x-y=4________(1)

15/x+y-5/x-y=-2________(2)

let 1/x+y=A and 1/x-y=Bua

therefore eqn 1 and 2 will become

10A+2B=4

15A-5B=-2

Now multiplying eqn 1 by -5 and eqn 2 by 2 we get

-50A-10B=-20

30A-10B=-4

Now by elimination method we have A=16/80=1/5

and B=1

but 1/x+y=A and 1/x-y =B

putting the values of A and B we get x+y=5____(3) and x-y=1______(4)

Now from eqn 3 we get x=5-y Now putting the value of x in eqn 4 we get y=2 and x=5-y i.e x=5-2=3. Therefore x=3 and y=2