To solve this we need to form 2 equations with only 2 variables.
x+4y-5z=-7
2x+y+5z=8
3x+5y=1
15x+10y+15z=35
6x+3y+15z=24
9x+7y=11
Now we need to use these to find x and y
9x+15y=3
9x+7y=11
8y=-8
y=-1
Therefore:
x=2
From this we can find that:
2(2)-1+5z=8
Therefore z=1
The answer is x=2, y=-1, z=1
