find x and y :10/x+y + 2/x-y=4 and 15/x+y - 5/x-y=-2
There are several ways of solving: try this one: let X=1/(x+y) and Y=1/(x-y):
10X+2Y=4, which reduces to 5X+Y=2; 15X-5Y=-2, substituting the new variables. We arrive at simultaneous linear equations.
So, multiplying the first equation by 3,  Read More: ...