By adding the 1st and third equation together, you get rid of z and end with 7x+8y=13. The second equation will be the second equation and 2 times the first equation, so the will yield 3x+8y=1. Now, you solve this system of equations and get x3, y=-1, and z=-4
The answer to this question is D and B
14.72
is the answer all you had to do was divide
1.67 is your answer 13.98 - 3.96=10.02 10.02 divided by 6 = 1.67
Hope I helped