Right triangle because a2<span> + b</span>2<span> = c</span><span>2</span>
Changing the order may not affect the answer in some situation, however it's not a rule.
Answer with positive exponent =
or 
Answer with negative exponent = 
===========================================================
Explanation:
The rule we use is

If we multiply two exponential expressions with the same base, then we add the exponents.
The base for each is 5. The exponents 4 and -7 add to -3.
This means

To convert to a positive exponent, we apply the reciprocal to the base. We go from 5, aka 5/1, to 1/5.
So, 
Answer:
20n
Step-by-step explanation:
Multiply square feet per person times the number of persons to find square feet.
The units analysis looks like this:

Answer:
Each friend receives 41 marbles, Wayne has 180 marbles left.
Step-by-step explanation:
Wayne starts with 303 marbles total. If he decides to give 123 of his marbles away to his friends, we can subtract this amount from his total to get how many he has left:
303 - 123 = 180 marbles left
We also want to know how many marbles each of his three friends receives. Since he wants to split them equally, we need to divide the number he is giving away by 3:
123 ÷ 3 = 41 marbles a piece to each friend