How do I do this?

The following system is solved by substitution. Which expression is substituted for z in the second and third equations?

x + 4y + z = –10
3x – 3y + 6z = –21
x + 2y + 2z = –10

Question

How do I do this?

The following system is solved by substitution. Which expression is substituted for z in the second and third equations?

x + 4y + z = –10
3x – 3y + 6z = –21
x + 2y + 2z = –10

anonymous · Answer

x – 4y – 10
x + 4y – 10
–x + 4y – 10
–x – 4y – 10

lalaly · Answer

z=-10-x-4y
so
z=-x-4y-10

anonymous · Answer

can you show me how?  sorry i just want to understand :)

lalaly · Answer

from the first equation
solve for z
can you?

lalaly · Answer

from the first equation
x+4y+z=-10
now solve for z
z=-10-x-4y

anonymous · Answer

sorry i didnt get notified that you posted!

anonymous · Answer

oh wow, i thought it was much more complex... thanks!

lalaly · Answer

its ok :D
im glad i can help