# Which expression is a polynomial?

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• Which expression is a polynomial?

Answer #1 | 28/12 2013 22:07
None of them
Answer #2 | 28/12 2013 22:12
f(x) = a_0x^n + a_1x^(n-1)+...+a_n is said to be a polynomial of degree n (provided a_0 ≠ 0), where a_i are constants and n is a positive integer. Thus D. x -√6 is a polynomial of degree 1.
Positive: 0 %
Answer #3 | 28/12 2013 22:12
D) a polynomial is a sum of integer powers of x (positive or zero to be exact). √6 is just a constant (i.e. x⁰) so is still a polynomial term. The others are not: A: 1/√x is x^(-1/2) <-- negative AND not an integer B: 1/x = x⁻¹ <-- negative exponents are not polynomial C: √x = x^(1/2) <-- not an integer exponent
Answer #4 | 28/12 2013 22:22
Answer D A) is ruled out because it has both a variable to fractional power as well as a negative power B) is ruled out because it has a negative power C) is ruled out because it has a variable with a fractional power D) however is ok because the fractional power [√(6)x⁰] is on the coefficient (6) not the variable x⁰