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.
Answer:
Step-by-step explanation:
Given: △ABC, D∈AC
, m∠BDC=m∠ABC
, AD=7, DC=9.
Solution: Let BC=x, From the given figure and the given information, it can be seen that △ABC is similar to ΔBDC by AA rule, thus using the proportionality theorem, we get

⇒
⇒
⇒
⇒BC=12
Now, calculate the similarity scale,
k=
=
Therefore, 
⇒
⇒
here's your solution,
A (5, 4) and B (5,-2) = 6 units
E (-2,-1) and F (-2,-5) = 4 units
C (-4,1) and D (1,1) = 5 units
G (3,-5) and H (6,-5) = 3 units
there is no questions to answer