Let the three numbers be x, y, and z.
If the sum of the three numbers is 3, then x+y+z=3
If subtracting the second number from the sum of the first and third numbers gives 9, then x+z-y=9
If subtracting the third number from the sum of the first and second numbers gives -5, then x+y-z=-5
This forms the system of equations:
[1] x+y+z=3
[2] x-y+z=9
[3] x+y-z=-5
First, to find y, let's take do [1]-[2]:
x+y+z=3
-x+y-z=-9
2y=-6
y=-3
Then, to find z, let's do [1]-[3]:
x+y+z=3
-x+-y+z=5
2z=8
z=4
Now that you have y and z, plug them into [1] to find x:
x+y+z=3
x-3+4=3
x=2
So the three numbers are 2,-3, and 4.
In the given image,
is 5. The correct option is the first option 5
<h3>Matrix notation</h3>
From the question, we are to determine which entry in the given matrix represents 
NOTE: For any entry denoted as
, it represents the entry in the <em>m</em>-th row and <em>n</em>-th column.
Thus,
represents the entry in the 2nd row and 3rd column.
In the given image, the entry in the 2nd row and 3rd column is 5.
Hence, in the given image,
is 5. The correct option is the first option 5
Learn more on Matrix notation here: brainly.com/question/2382978
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Answer:
x= -7
Step-by-step explanation:
have a good day
Well divide them. 2/3=0.666 repeated. So use a bar over the top of the third six.