Question

Okay I know this is really simple but for some reason I keep getting the wrong answer. I'm probably making some dumb math error in my math:
Solve the following system of equations:
4x - 2y - z = -5
x - 3y + 2z = 3
3x + y - 2z = -5

Answer 1

Oh these are the answer choices btw:

A. (0, 1, 3)

B. (0, -1, 3)

C. (0, 1, -3)

D. (0, -1, -3)

Answer 2

Adding the 2nd and 3rd equations together seems to help.

Answer 3

Because it leaves you with only two
4x-2y-z=-5
4x-2y=-2

Answer 4

and since (4x-2y)=(-2), you can use that in the first equation
(4x-2y)-z=-5
-2-z=-5

Answer 5

z=3

Answer 6

so plug that into -2-z=-5 and that gives you -5=-5?

Answer 7

You can't plug an answer in an equation you just used to find that answer, you would just get a true statement.

Plug it in the original equations.

Answer 8

So I think the answer is B...

Answer 9

x-3y+2*3=3
3x+y-2*3=-5

x-3y+3=0
3x+y-1=0

(y)=(1-3x)
x-3(y)+3=0
x-3(1-3x)+3=0
10x=0

[x=0]

Answer 10

Ahhhhh...got it!

Answer 11

Thanks

Answer 12

No problemo :)