Answer:
Which i think is the first one, there may just be a typing error.
Step-by-step explanation:
A polynomial of order n has the following format:

In which a is the leading coefficient,
are the roots.
If a root appears m times, they are said to have multiplicity m.
Leading coefficient of 1 and roots 21 and 31 with multiplicity 1

So the correct answer is:

Which i think is the first one, there may just be a typing error.
Answer is A) AC= 20 and angle A=37°
Dilated by factor of 4 means enlarged by 4 ( multiply by 4)
The angle stays the same no matter how much you increase or decrease the size
And AC= 5 x4= 20