Solve System of Equations: Gaussian Elimination

[psychfan29]

Solve the following system of equations using Gaussian elimination:
3w+10x-2y+3z=55
w+12x-11y-z= 69
-3w-6x-5y-10z=-47
-3w+9x+5y+4z=-1

Here's what I did so far:
swap R1 and R2 (row 1 and row 2)
-3R1+R2 (multiply row 1 by -3 and add row 2 to that product)
3R1+R3
3R1+R4

Now, after that I think I may have made a mistake because I eventually get some very odd fractions that could not possibly be correct. Can somebody tell me what the steps are?

 

[exk]

I followed your initial steps and finishing the elimination works out just fine despite any fractions. Make sure your arithmetic is correct and don't be afraid of fractions.