16. 5x^3 y^-5 • 4xy^3
20x^4y^-2
20x^4 • 1/y^2
=20x^4/y^2
17. -2b^3c • 4b^2c^2
= -8b^5c^3
18. a^3n^7 / an^4 (a^3 minus a = a^2 same as n^7 minus n^4 = n^3)
=a^2n^3
19. -yz^5 / y^2z^3
= -z^2/y
20. -7x^5y^5z^4 / 21x^7y^5z^2 (divide -7 to 21 and minus xyz)
= -z / 3x^2
21. 9a^7b^5x^5 / 18a^5b^9c^3
=a^2c^2 / 2b^4
22. (n^5)^4
n ^5 x 4
=n^20
23. (z^3)^6
z ^3 x 6
=z^18
Option A: z + 1
Option B: 6 + w
Option D: 
Solution:
Let us first define the polynomial.
A polynomial can have constants, variables, exponents and fractional coefficients.
A polynomial cannot have negative exponents, fractional exponents and never divided by a variable.
<u>To find which expressions are polynomial:</u>
Option A: z + 1
By the definition, z + 1 is a polynomial.
It is polynomial.
Option B: 6 + w
By the definition, 6 + w is a polynomial.
It is polynomial.
Option C: ![y^{2}-\sqrt[3]{y}+4](https://tex.z-dn.net/?f=y%5E%7B2%7D-%5Csqrt%5B3%5D%7By%7D%2B4)
![y^{2}-\sqrt[3]{y}+4=y^{2}-{y}^{1/3}+4](https://tex.z-dn.net/?f=y%5E%7B2%7D-%5Csqrt%5B3%5D%7By%7D%2B4%3Dy%5E%7B2%7D-%7By%7D%5E%7B1%2F3%7D%2B4)
Here, y have fractional exponent.
So, it is not a polynomial.
Option D: 
By the definition,
is a polynomial.
It is polynomial.
Hence z + 1, 6 +w and
are polynomials.
About 8,456.17849
Rounded: 8,456.18
Answer:
the 4th one
Step-by-step explanation: