Question

Solve: 

4/x + 5/y = 7;

3/x + 4/y = 5

Answer 1

Replacing (1/x) by m and (1/y) by n in equations (I) and (II), we get

4m + 5n = 7 . . . (III) 

3m + 4n = 5 . . . (IV)

On solving these equations we get 

m = 3, n = -1

Solution of given simultaneous equations is (x, y) = (1/3, -1)