Answer:
C. 2(x + 10)(x - 10)
Step-by-step explanation:

Answer:
The middle two expressions shown are not polynomials
Step-by-step explanation:
Polynomial terms have positive integer exponents on any variables. A 2/3 power is not an integer exponent. Division by y is equivalent to an exponent of -1, which is not a positive integer.
Answer:
c on edg
Step-by-step explanation:
The answer is 9 : 5
36:20
18:10
9:5