Is there a typo in x_1 for the particular solution in this answer?

[s3a]

Homework Statement

In question #1(b)'s answer, should x_1 = 4 (instead of -4)?

Homework Equations

PDF of problem #1(b):
https://www.dawsoncollege.qc.ca/pub...ms/201-nyc-05-computer_science-winter2011.pdf

Reduced row echelon form of the matrix I obtained from the given equations (in problem #1):
http://www.wolframalpha.com/input/?...ix+{{1,2,-2,3,2},{2,5,-3,4,5},{5,9,-8,11,12}}

The Attempt at a Solution

If t = 0, then it should be the case that x_3 = 1 + 2*0 = 0, x_2 = 0 and that x_1 = 4 + 0 = 4 ≠ -4.

Am I right and the answer is wrong?

 

[SammyS]

Homework Statement

In question #1(b)'s answer, should x_1 = 4 (instead of -4)?

Homework Equations

PDF of problem #1(b):
https://www.dawsoncollege.qc.ca/pub...ms/201-nyc-05-computer_science-winter2011.pdf

Reduced row echelon form of the matrix I obtained from the given equations (in problem #1):
http://www.wolframalpha.com/input/?i=reduced+row+echelon+form+of+matrix+{{1,2,-2,3,2},{2,5,-3,4,5},{5,9,-8,11,12}}

The Attempt at a Solution

If t = 0, then it should be the case that x_3 = 1 + 2*0 = 0, x_2 = 0 and that x_1 = 4 + 0 = 4 ≠ -4.

Am I right and the answer is wrong?

Yes.
That is surely a typo.

If t=0, then x₁ = 4 .

 

[s3a]

Great, so it's not just me. Thanks. :)