Which of the following is an example of a system of three linear equations in theee variables A) y+z=12
3y+z=18
2y-4z=21

B) x+y+7z=8
2x+z-3w=2
x-4y+w=1

C) x+2x=15
2x=12
2x+x-3x=20

D) x+y+z=5
2x-3y+z=7
x+2y-4z=2

1) no, because a solution must be an ordered triple pair (x,y,z)

2) { x+y+z=5    

   { 2x-3y+z=7      

   { x+2y-4z=2

3) infinity many solutions

4) use equations (1) and (2) to eliminate y

5) solve one equation for one of its variables  

Step-by-step explanation:

should be 100% on the quick check if you put those answers

solution:

as, mean is defined as sum of all the observations divided by total number of observations.

and , median is mid value of the data whether arranged in ascending order or descending order.

consider, roadsters:

2,3,4,5,6,7,8,9

mean =

also, median= , because number of observations is even, so median is mean of two mid values.

now, coming to bandits

2,3,4,5,6

mean =  

median = 4, as number of observations is odd.

so, roadsters has greater median as well mean than bandits.

→option a is true about the repairs performed on 2 types of cars:

bandits have lower median and mean than roadsters.

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