solve the system by substitution
{-x-y-z=-8
-4x+4y+5z=7
2x+2z=4}

Question

solve the system by substitution 
{-x-y-z=-8
-4x+4y+5z=7
2x+2z=4}

jango_in_dtown · Answer

2x+2z=4 so (x+z)=2

nevillesnetwork · Answer

is this a multiple choice question, are there answers to choose from?

jango_in_dtown · Answer

put this in the first equation 
-y-(x+z)=-8i.e. -y-2=-8 i.e. y=8-2=6

nevillesnetwork · Answer

jango is correct

faiithhh · Answer

no, not multiple choice. i have to show my work, but i don't know how to do any of this.

jango_in_dtown · Answer

then use the results in equation 2 , which you can write
-4x+4*6+5z=7i.e. -4x+5z=7-24=-17
i.e. 4x-5z=17

jango_in_dtown · Answer

now we need to solve x+z=2
and 4x-5z=17,

faiithhh · Answer

okay... woah... i mean like, i literally don't know how to do any of this. Everything you've said has gone right over my head...

jango_in_dtown · Answer

Do you know what is the method of substitution?

faiithhh · Answer

not really, no..

jango_in_dtown · Answer

Then you must first learn the theory. :)

faiithhh · Answer

could you teach me, oh great & wise one? xD