Question 169534
x=-2   y=5   z=-3

 1. x+y-z (-2 +5 -(-3) )=(2*(-1+1)+3-(-3))=(2(-1+1)+3(1+(-)^2))for all intents here =(3(1+1))=6 no 'division by (1-1)' so arithmetic suffices.

  2. 2y-2
  ----------=(2*5-2)/(-2)=(5-1)/(-1)=(4+(1-1))/(-1) 'here' =-4
     x
                                 
3. x   +   31
  ----    ----- =-2/5/(-3)+31/30=2/15+31/30=4/30+31/30=35/30=7/6     
  y*z      30

4. z -  y - 12.7=(-3)-(5)-(12.7)=-20.7=-20-7/10=-207/10