Answer:
15cm
Step-by-step explanation:
scale factor =image diatace/object distance
0.75=x/20
0.75×20=x
15=x
: .x=15cm
She can expect to pick a black marble 125 times
C. 7.2°F is warmer than 7.0°F but colder than 7.6°F.
Answer with Step-by-step explanation:
We are given that

For each real number 
To prove that f is one -to-one.
Proof:Let
and
be any nonzero real numbers such that

By using the definition of f to rewrite the left hand side of this equation

Then, by using the definition of f to rewrite the right hand side of this equation of 

Equating the expression then we get




Therefore, f is one-to-one.