Let plug the variable into the equation.


We can conclude that this is incorrect because

does NOT equal

The correct answer would be:

;

; or

or

All

of these are correct answers.
Answer:
Step-by-step explanation:
2915 can stay as it is; 15.458 should be rounded down to 15. Then we have
2915-15, or 2900 (which is a very reasonable estimate).
Answer:
Step-by-step explanation:
I assume you need help with the first picture:
Let 
Then

Clearly you can see that the sum of 2 rational numbers gives a rational number.
Answer:
negative 5
Step-by-step explanation:
4-9= -5
Answer:
A. 140
Step-by-step explanation:
width times height times length
5·7·4=140