C. 5
Step-by-step explanation:
The coeff of 

Is 15. 
So by that we can write 3m = 15 
m is 5.
 
        
             
        
        
        
Answer:
Step-by-step explanation:
to find out t, we divide by 3 both sides
-2/3=t
t=-2/3
 
        
             
        
        
        
Answer:
C. 3
Step-by-step explanation:
Given expression is:

We know that the rules of exponents are used to solve these kind of questions.
When there is exponent on exponent like in this question 1/7 has an exponent of 7 , the exponents are multiplied.
So,

The 7's will be cancelled out and remaining power will be 1

Hence, option C is correct ..