17. Yes!! SAS theorem
18. Yes !! SSS theorem
19. Yes !! SSS theorem
20. I don’t think so
There is .82% chance they will have the same bdays
Answer:

Step-by-step explanation:
To factor the equation, break it into two binomials which multiply to make the equation. To write these binomials (x+a)(x+b), find factors which multiply to -20 and add to -1 for a and b.
20: 1, 2, 4, 5, 10, 20
-5+4 = -1

Answer:
A. 2.8 billion years old
Step-by-step explanation:
1/16 = (1/2)^4, so 4 half-lives have elapsed.
4 · 0.700 billion years = 2.8 billion years
The rock is 2.8 billion years old.