Solve for x and y:

We have


and


Lets simplify these equations. Assuming p = 1/(x + y) and q = 1/(x – y),



10p + 2q = 4 …(i)


Also,


15p – 9q = - 2 …(ii)


To solve these equations, we need to make one of the variables (in both the equations) have same coefficient.


Lets multiply eq.(i) by 9 and eq.(ii) by 2, so that variable q in both the equations have same coefficient.


Recalling equations (i) & (ii),


10p + 2q = 4 [×9]


15p – 9q = - 2 [×2]



120p = 32


p = 4/15


Substitute p = 4/15 in eq.(i)/eq.(ii), as per convenience of solving.


Thus, substituting in eq.(ii), we get


15(4/15) – 9q = - 2


4 – 9q = - 2


9q = 4 + 2 = 6


q = 2/3


Thus, p = 4/15 and q = 2/3


As p = 1/(x + y),



4x + 4y = 15 …(iii)


And q = 1/(x – y)



2x – 2y = 3 …(iv)


Multiplying eq.(iv) by 2, we get


4x – 4y = 6 …(v)


and then adding equations (iii) and (v) to obtain x and y,


(4x + 4y) + (4x – 4y) = 6 + 15


8x = 21


x = 21/8


Putting the value of x in equation (iv), we get


2(21/8) – 2y = 3


21/4 – 2y = 3


2y = 21/4 – 3 = 9/4


y = 9/8


Hence, we have x = 21/8 and y = 9/8


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