A polynomial is an expression consisting of variables and coefficients, that involves only the operations of addition, subtraction, multiplication, and non-negative integer exponents of variables.
Therefore your answer is [tex]x-\sqrt7[/tex]
[tex]\sqrt{7x}[/tex] NOT, because x is in square root.
[tex]\dfrac{7}{\sqrt{x}}[/tex] NOT, because x is in square root and is in the denominator
[tex]\dfrac{7}{x^2}[/tex] NOT, because x² is in the denominator.
