Question 666632
  <pre><font face = "Tohoma" size = 3 color = "indigo"><b> 
Hi,
x+5y-4z=-10
<u>2x-y+5z=-9</u>    ||eliminating z
 13x + 21 y = -86
2x-y+5z=-9
<u>2x-10y-5z=0</u>   ||eliminating z
 4x - 11y = -9 
<u> 13x + 21 y = -86</u>
   21x = -105,  x = -5   and y = -1  and z = 0