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

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

jamesj · Answer

Well, you have to use the first equation.  What is the expression for z
 from the first equation?

amistre64 · Answer

you have to use the first?

amistre64 · Answer

i see it know, read right over it :)

jamesj · Answer

Yes, because you are substituting into the other two equations.

@amistre: are you at college?

amistre64 · Answer

I am :)

amistre64 · Answer

i aint got internet at the house

anonymous · Answer

i dont get it..

amistre64 · Answer

gont get what, that your working with 3 variable equations when the audacity of the teachers expect you to solve when they havent even tried to give you any preparatory means to do so?

anonymous · Answer

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

amistre64 · Answer

solve this equation for z:

x + 4y + z = –10

how would we be able to do that, not a real value, just any psuedo value

amistre64 · Answer

see, you have 4 options to choose from even ....

anonymous · Answer

kay your no help.

amistre64 · Answer

define "help"

anonymous · Answer

i got it, thanks.

amistre64 · Answer

cool, i figured you could :)