substitution:
z = -19-2x+3y
so use that to get
5x+y-(-19-2x+3y) = -7
-x+6y-(-19-2x+3y) = 35
or
7x-2y = -26
x+3y = 16
Now you have x = 16-3y, so that gives
7(16-3y)-2y = -26
-23y = -138
y = 6
so, x=16-3y = 16-3*6 = -2
so, z = -19-2x+3y = -19-2(-2)+3*6 = 3
so, the solution is (-2,6,3)
elimination:
2x-3y+z=-19
5x+y-z=-7
-x+6y-z=35
add #1 and #2, then #1 and #3
7x-2y = -26
x+3y = 16
add 3*#1 to 2*#2
21x-6y = -78
2x+6y = 32
or
23x = -46
x = -2 as above
What is the solution?
2x-3y+z=-19
5x+y-z=-7
-x+6y-z=35
1 answer