Need answer fast with all the steps included please

Two customers went to a post office. first customer paid $12 for 14 and 5 envelopes the second paid 24.80 for 10 postcards and 15 envelopes. what is cost of each envelope?

Which expression do you get when you eliminate the negative exponents of 4a^2 b^216a^-3 b

Reinel saves 30% of every pay check. his paycheck last week was 560$. how much did reniel save last week?