Answer:
its C
Step-by-step explanation:
Answer with Step-by-step explanation:
Let F be a field .Suppose
and 
We have to prove that a has unique multiplicative inverse.
Suppose a has two inverses b and c
Then,
where 1 =Multiplicative identity

(cancel a on both sides)
Hence, a has unique multiplicative inverse.
Answer:
she only needs to work ten hours
Explanation: if you subtract 45 from 115 you well end up with 70 a and if you work for ten hours 7 ×10=70 so you would have enough.