Question

PLEASE HELP!!!
Use the substitution method to solve the following system of equations.
x + 2y - z = 2
3x + y - 2z = -15
3x + 4y - 3z = -2

Answer 1

a) (7, -4, -1)
b) (-7, -4, 1)
c) (7, -4, 1)
d) (-7, 4, -1)

Answer 2

x = 2-2y+z
substitute into the 2nd equation:
3(2-2y+z) + y - 3z = -15
solve for y in this one, and then substitute both into the last equation.

Answer 3

okay thanks!

Answer 4

my final answer is b) (-7, -4, 1)

Answer 5

Guessing won't work here...
Let's try out B:
-7+2(-4) -1 = -7 - 8 - 1 = -16 (the first equation is already wrong)

Answer 6

no i didnt guess i actually worked it out

Answer 7

There's a mistake in your solution somewhere then

Answer 8

i guess i did it wrong tho

Answer 9

ya i dont know this is hard

Answer 10

Try d

Answer 11

okay

Answer 12

i tried and i think i messed up but imma just go with d

Answer 13

i tried all the equations

Answer 14

Verify it using my method

Answer 15

i dont know how

Answer 16

IS THE ANSWER D????

Answer 17

or could you check for me? and show me how because im confused

Answer 18

ive been stuck on this question for over 2 hours and i need to turn this assignment in asap could you help?

Answer 19

\[\large 3x+y-2z=-15\]Rewriting the second equation, moving some stuff around, gives us,
\[\large \color{green}{y=-15-3x+2z}\]

\[\large x+2\color{green}{y}-z=2\]Plugging this into the first equation gives us,\[\large x+2\color{green}{\color{green}{(-15-3x+2z)}}-z=2\]

Now we've successfully written one of our equations in terms of only 2 variables.
You're suppose to solve this using substitution like this?
Wow this is going to be a long process :D lol

Answer 20

Yah plugging in the options is probably a better idea.. hmm

Answer 21

i think the answer is d (-7,-4,1)

Answer 22

i worked it out and thats what i got.

Answer 23

d says (-7, 4, -1), not (-7, -4, -1).

You're just looking for someone to check your work I guess..? :o
Yah good job. That's the correct answer.

Answer 24

my bad i accidentally put the negative on the 4

Answer 25

@zepdrix so the correct answer is d (-7,4,1)

Answer 26

Yes, the correct answer is d, you keep writing it incorrectly though lol :)

(-7, 4, -1) not (-7, 4, 1)

Answer 27

sorry haha its late. thank you though

Answer 28

XD