Before I go on and give you the problenms let me explain. i am not some lazy kid trin to get people to do my homework over the internet. I am freshman that just recently skippeda garde in math and I need some help. The problems below are from my pop quiz out of the text book i gotta hand in on monday. I can't ahve my aad or mom checkin this cause they have no clue on this but i did the problems and need feed bac.

solve the system using linear combination method
12. 3x+ 2y-z=8
-3x+4y+5z=-14
x-3y+4z=-14

(my answer was (1,1,-3))

16. x+y-2z=5
x+2y+z=8
2x+3y-z=13

(my answer was infinite solution)

18. -2x+y+6z=1
3x+2y+5z=16
7x+3y-4z=11

(my answer was in fraction form but she said no solutions were fractions)

#12 and 16 are correct

check your arithmetic for 18
I got (4,-3,2) and those values work for all 3 equations.

(You do know that you can check your answer yourself by merely substituting your values into each equation, don't you?)