[SOLVED] using matrices to solve for a system of equations using gaussian elimination

my system of equations is

x-4y+3z-2w=9

3x-2y+z-4w= -13

-4x+3y-2z+w= -4

-2x+y-4z+3w=-10

my augmented matrix is

1 -4 3 -2 9

3 -2 1 -4 -13

-4 3 -2 1 -4

-2 1 -4 3 -10

i don't know how to plug this into my calculator to get an answer, but i got these answers using the row operations:

x= -19.5

y= -4.5

z= 0.5

w= 4.5

these answers don't seem correct, so i was wondering if anyone could tell me the actual answers when plugged into the calculator, so i could figure out what i did wrong or ask for more help.