<em><u>The polynomials are:</u></em>
![x^4+3x^3-5x^2-7x+20](https://tex.z-dn.net/?f=x%5E4%2B3x%5E3-5x%5E2-7x%2B20)
![x^3-2x^2+x-12](https://tex.z-dn.net/?f=x%5E3-2x%5E2%2Bx-12)
![x^2+3x^5-6x+12x^3](https://tex.z-dn.net/?f=x%5E2%2B3x%5E5-6x%2B12x%5E3)
<em><u>Not a polynomial are:</u></em>
![4\sqrt[3]{x} -\sqrt{x} -20](https://tex.z-dn.net/?f=4%5Csqrt%5B3%5D%7Bx%7D%20-%5Csqrt%7Bx%7D%20%20-20)
![\frac{5}{x^3}-\frac{1}{x^2}+\frac{8}{x}-40](https://tex.z-dn.net/?f=%5Cfrac%7B5%7D%7Bx%5E3%7D-%5Cfrac%7B1%7D%7Bx%5E2%7D%2B%5Cfrac%7B8%7D%7Bx%7D-40)
![x^{-3}-x^{-2}-6x^{-1}+8](https://tex.z-dn.net/?f=x%5E%7B-3%7D-x%5E%7B-2%7D-6x%5E%7B-1%7D%2B8)
<em><u>Solution:</u></em>
Polynomial is an expression with variables and coefficients,
Which involves only the operations of addition, subtraction, multiplication, and non-negative integer exponents of variables
<em><u>Option 1</u></em>
![4\sqrt[3]{x} -\sqrt{x} -20](https://tex.z-dn.net/?f=4%5Csqrt%5B3%5D%7Bx%7D%20-%5Csqrt%7Bx%7D%20%20-20)
Polynomial does not include roots
This is not a polynomial equation
<em><u>Option 2</u></em>
![x^4+3x^3-5x^2-7x+20](https://tex.z-dn.net/?f=x%5E4%2B3x%5E3-5x%5E2-7x%2B20)
This is polynomial expression involving addition and subtraction between terms with non-negative integer exponents of variables
<em><u>Option 3</u></em>
![\frac{5}{x^3}-\frac{1}{x^2}+\frac{8}{x}-40](https://tex.z-dn.net/?f=%5Cfrac%7B5%7D%7Bx%5E3%7D-%5Cfrac%7B1%7D%7Bx%5E2%7D%2B%5Cfrac%7B8%7D%7Bx%7D-40)
This is not a polynomial. This equations involves negative integer exponents of variables
<em><u>Option 4</u></em>
![x^3-2x^2+x-12](https://tex.z-dn.net/?f=x%5E3-2x%5E2%2Bx-12)
This is a polynomial involving addition and subtraction between terms with non-negative integer exponents of variables
<em><u>Option 5</u></em>
![x^{-3}-x^{-2}-6x^{-1}+8](https://tex.z-dn.net/?f=x%5E%7B-3%7D-x%5E%7B-2%7D-6x%5E%7B-1%7D%2B8)
This is not a polynomial. This equations involves negative integer exponents of variables
<em><u>Option 6</u></em>
![x^2+3x^5-6x+12x^3](https://tex.z-dn.net/?f=x%5E2%2B3x%5E5-6x%2B12x%5E3)
This is a polynomial involving addition and subtraction between terms with non-negative integer exponents of variables