Bro I cannot, my brain cannot

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?

F(x) = 1/x g(x)=x-4 can you evaluate (g*f)(0) ? why or why not?

Darren earned $663.26 in net pay for working 38 hours. he paid $118.51 in federal and state income taxes, and $64.75 in fica taxes. what was darren's hourly wage? question options: $17.45 $19.16 $20.57 $22.28