Question 265448
36x-15y+50z=-10   ----------------------- 1
2x+25y=40         ----------------------- 2
54x-5y+30z=-160   ----------------------- 3

multiply eq. 1 by 3 and eq. 3 by 5 and then subtract both (to eliminate z)

so we get 108x-45y+150z=-30 
          270x-25y+150z=-800

          -162x-20y=770 

now multiply eq.2 by 81 and add to the above eq.
  
we get 2005y=4010

so y=2      
   
from eq. 2 

2x+50=40 => 2x=-10 
=> x=-5

from eq.1 -180-30+50z=-10

so 50z=200

=> z=4

so x=-5, y=2, z=4