Answer:
m ≥ 0
Step-by-step explanation:
Since the cost is represented by c = 0.12m, the domain should be a positive number, this is because number of minutes can't be written in negative. Therefore, the most reasonable number for the domain would be the set of positive whole numbers which means, m≥0.
The sum of the first n odd numbers is n squared! So, the short answer is that the sum of the first 70 odd numbers is 70 squared, i.e. 4900.
Allow me to prove the result: odd numbers come in the form 2n-1, because 2n is always even, and the number immediately before an even number is always odd.
So, if we sum the first N odd numbers, we have

The first sum is the sum of all integers from 1 to N, which is N(N+1)/2. We want twice this sum, so we have

The second sum is simply the sum of N ones:

So, the final result is

which ends the proof.
Answer:
Student 3
Step-by-step explanation:
Part of the 3-4-5 Pythagorean triples.
Answer:
For every pound that the package weight increases, the price of sending it increases by $3.80.
Step-by-step explanation:
The coefficient 3.80 multiplies the variable x (package weight), so if x is 1 pound the cost increase $3.80, if x is 2 pound the cost increase 2*3.80 = $7.6, and so on. Generally speaking, for every pound that the package weight increases the cost increases by $3.80.