Answer:
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Answer:

Step-by-step explanation:
Answer:
5
Step-by-step explanation:
n + m -2(m-m)
Combine like terms
n+m+2(0)
n+m
Let m=3 and n=2
2+3
5
Answer:
Option D.
3 equations with 3 variables
Step-by-step explanation:
The coordinates of a point in space must necessarily have 3 components. One to describe the distance on the x axis, another to describe the distance on the y axis to the point, and a third to describe the distance on the z axis.
If we have three variables, then 3 equations are needed to solve the system. With less than 3 equations it would be impossible to solver the system.
Therefore the correct answer is option D.
3 equations with 3 variables