A) prove that the set in 14b is closed, by showing that its complement is open (directly from the definition of open sets). b) prove that the same set is closed, using the generalization of proposition 1.4.9 which is true for maps from c to r or rm as well.

ranks (& how to earn them):

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-ambitious   (needs at least 250 points & 0 brainliest answers)

-virtuoso (needs at least 500 points & 5 brainliest answers)

-expert   (needs at least 1,000 points & 10 brainliest answers)

-ace (needs at least 3,000 points & 15 brainliest answers)

-genius   (needs at least 15,000 points & 50 brainliest answers)

how to award brainliest:

you must wait until 2 people answer to award brainliest. i'm pretty sure that it should be next to the "" and "comments" buttons.  

there still no table

answer:

some responsibilities that come with having a checking account -

1. we have to maintain check register with exactness to avoid checks being returned for insufficient funds which is called bouncing a check.

2. we need to update our check register each time we make a transaction using a convenience card. updating check register will   save   us from   overdrawing of checking account.

3. read the agreement the bank gave you when you signed up for our checking account. this includes all the fees and the minimum balance we need to keep in our account to avoid maintenance charges.  

explanation:

note : -   checking account is a transactional deposit account. we can use it to deposit and withdraw funds. money in a checking account is very liquid. it   can be withdrawn using electronic debits, automated cash machines, or checks among other methods.