Lets start with question 2. In this case, we have

By substituting g=1|/4, we get

which gives

But this result is incorrect because 39 is equal to 39 not greater than 39. So, the answer is false.
Question 3.
In this case, we have the following expression:

By substituting f = 12, we have

which gives

This result is correct because the symbol

means "equal or less than". Then, our last result means 3 equal or greater than 3. So, the answer is true because 3 is equal to 3.
Question 4.
In this case, the expression is

By substituting r=23, we get

On the left hand side, we have 121-98=23, then, our last result is equal to

and this is true, because the symbol

means "greater or equal to".