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

nincompoop · Answer

what does substitution mean?

anonymous · Answer

.....

nincompoop · Answer

do you know what it means?

anonymous · Answer

Please don't bother helping me if you don't know that..

nincompoop · Answer

I don't know it? I am asking you if you knew it
I wouldn't bother helping if I didn't know anything

nincompoop · Answer

but I guess you need help beyond math, because your attitude seems to be a problem too

anonymous · Answer

Jesus, go away.

nincompoop · Answer

Jesus is not my name :P

anonymous · Answer

How old are you, 12?

anonymous · Answer

girls, stop fighting, you're both pretty. now can I go home?

anonymous · Answer

emily - solve the first equation for y and the third equation for z. use the expressions you find for y and z to solve for x in the second equation.
have fun

anonymous · Answer

Can you show me step by step?

anonymous · Answer

I just told you the steps. showing would be doing the work for you.

anonymous · Answer

I can show you a simpler case.
x-y=0
x+y=2

a 2x2 system of equations

solve the first equation for x
x=y

use the expression for x in the second equation to make the second equation have only one variable
y+y=2
solve for y
2y=2, y=1
then solve for x
x=y=1

anonymous · Answer

have fun

anonymous · Answer

so, it's 2y=2?
Then x=y=1? I dunno what to do next.

anonymous · Answer

I was showing the process in a simpler case, nothing to do with your problem.
follow the steps I outlined earlier to solve your problem.

anonymous · Answer

please tell me what to do. I'm desperate. :(

nincompoop · Answer

so do you know what it means to substitute?

anonymous · Answer

I did

anonymous · Answer

solve the first equation for y and the third equation for z. use the expressions you find for y and z to solve for x in the second equation.

anonymous · Answer

You aren't very helpful @Peter14

anonymous · Answer

solve the first equation for y
y=(something)
solve the third equation for z
z=(someotherthing)

use the expressions for y and z in the second equation to solve for x
-4x+4y+5z=7
-4x+4(something)+5(someotherthing)=7
(something) will have a z-term in it too, so put (someotherthing) in its place, then solve for x.

anonymous · Answer

...you could have just told me you wanted me to do it for you at the beginning.

usukidoll · Answer

oh no they were helpful...it's you who is being rude. ;)
And by the way, Matrix style for the win!

usukidoll · Answer

2 x 3 augmented matrix but heyyyy if it's solve by substitution, it means algebra style and that's tedious :D

anonymous · Answer

How on earth am I being rude?

anonymous · Answer

Asking for help? Stop picking on me for wanting fluttering help. Jesus Christ.

usukidoll · Answer

calling nin Jesus is one which is using the lord's name in vain. Two we help users, not spoon feed answers.

usukidoll · Answer

whatever I spent 7 years on Mathematics...so >:P

anonymous · Answer

How old are you?

usukidoll · Answer

none of your business

anonymous · Answer

UsukiDoll, this post is no longer worth our time.

anonymous · Answer

Hm. Must be old.

usukidoll · Answer

duh! And yeah let's go @Peter14

anonymous · Answer

So, you're old, with a my Little Pony picture set as your profile picture, on this site helping kids at midnight? 0_ o

usukidoll · Answer

And you're being disrespectful beyond recognition.

usukidoll · Answer

so what there are bronies out there with the my little pony craze

anonymous · Answer

No, asking for help. Just getting pissed cause of people like you

usukidoll · Answer

aren't you in connections academy?

anonymous · Answer

Nope.

anonymous · Answer

you aren't asking for help anymore, I gave you all the help you need. I stopped one step short of doing the problem for you.

usukidoll · Answer

what Peter said

anonymous · Answer

stop. get up and get a drink of water. look at my explanation. then do the math.

anonymous · Answer

you can do it.

anonymous · Answer

No. You didn't do pellet, peter pan

anonymous · Answer

peter rabbit, get it right!

usukidoll · Answer

oh yes he did. It's you who is not doing the problem

anonymous · Answer

Oh, yes. That's it xD

anonymous · Answer

solve the first equation for y
y=(something)
solve the third equation for z
z=(someotherthing)

use the expressions for y and z in the second equation to solve for x
-4x+4y+5z=7
-4x+4(something)+5(someotherthing)=7
(something) will have a z-term in it too, so put (someotherthing) in its place, then solve for x.

good luck :)

nincompoop · Answer

even if she learned that portion of math I doubt people will have patience and even consideration to deal with a person who is both ingrate and bad-mannered