Question

If x and y in the equations

Answer 1

We can let
   a = 1/(x-1)
   b = 1/(y+2)
and rewrite the equations as
   2a - b = 10
   a + 3b = -9
Using the first to write an expression for b, we get
   b = 2a - 10
Substituting this into the second equation gives
   a + 3(2a -10) = -9
   7a -30 = -9 . . . . . . . . simplify
   7a = 21 . . . . . . . . . . .add 30
   a = 3
   b = 2·3 - 10 = -4

Now, we can find x and y.
    3 = 1/(x -1)
    x - 1 = 1/3
    x = 1 1/3 = 4/3

    -4 = 1/(y +2)
    y +2 = -1/4
    y = -2 1/4 = -9/4

Then the desired sum is
    x + y = 4/3 -9/4 = (16 -27)/12
    x + y = -11/12

The appropriate choice is ..
   c. -11/12