Question

Solve the following system of equations.

4x + 7y – 2z = 0
3x – 5y + 3z = 9
3x + 6y – z = 1


Choices:

A.(1, 0, 2)
B.(–1, 0, –2)
C. (1, 0, –2)
D.(–1, 0, 2)

Answer 1

do you want help or just an answer?

Answer 2

can you do both please?

Answer 3

Subtract the second equation from the third. That'll eliminate your x variable

Answer 4

oh ok thank you

Answer 5

what did you get?

Answer 6

I'm still working it out

Answer 7

is it C?

Answer 8

Close, but no

Answer 9

Lets assume your x and y are correct.

Answer 10

If we plug into 3x + 6y – z = 1

We have:

3 + 0 - z = 1
3 - z = 1
-z = -2
z = 2

Answer 11

But if we assume that z and y are correct:

3x + 0 - (-2) = 1
3x + 2 = 1
3x = -1
x = -1/3

Answer 12

So there's something wrong here.

Answer 13

Can you show some of your work and we can see where you went wrong?

Answer 14

ok I subtracted the second and third equation to get
-11y+5z=10

Answer 15

then I got kind of confused from there

Answer 16

Oh, well that's not quite right.

3x -5y + 3z = 9
- (3x + 6y -z) = -1
============
0x -11y +4z = 8

Answer 17

oh I got it wrong from the beginning

Answer 18

Actually though, as tempting as that is. I'm going to change my vote. Lets eliminate the z's

Answer 19

That might be eaiser:

Lets subtract 3 times the 3rd equation from the second one.

Answer 20

is it D?

Answer 21

A(1,0,2)