How in the heck do you answer this math question? and what kind of problem is this called?

Question

8. Saying that 4 < x < 9 is equivalent to saying what about x ?

A. 0 < x < 5
B. 0 < x < 65
C. 2 < x < 3
D. 4 < x < 9
E. 16 < x < 81

I dont necessarily want the answer (its not for homework, im studying for a test). I need help on getting the answer. I would look online but im not sure what the problem itself is called

Answer 1

The problem is an inequality. The answer is E. If 4 < (sqrt)x, then 16 (or 4 ^2) will be less than (sqrt)x^2, which is of course x; and if the square root of x < 9, then (sqrt)x^2 is less than 81. This would be far less confusing if computer keyboards had square root signs.

Answer 2

Basically the "<" symbol reads as "less than". So read it as:



4 is less than x and x is less than 9. So, basically x is between 4 and 9.



You can rule out A as x might not be less than 5. It could be 6 for example. (4 is less than 6 and 6 is less than 9).



Repeat this process for each answer. Basically the only answer that is right is D

Answer 3

Well D is the same equation thus true. You just have to look at the numbers x is greater then 4 so its gotta be like 5 or something. x is also less than nine so your options would be from 4.00000001 or whatever to 8.999999 if that makes sense.