Quiz: Polynomial Functions and Theorems — 11 questions

Detailed questions and answers

1. Which condition is required for an expression to have the standard polynomial form of degree nn?

Its variable may appear in a denominator if the coefficients are real
Its exponents are nonnegative integers and its coefficients are real
Its exponents may include fractional values and its coefficients are integers
Its exponents may include negative integers and its coefficients are real

Its exponents are nonnegative integers and its coefficients are real

Explanation

A polynomial uses nonnegative integer exponents, real coefficients, and a nonzero leading coefficient. Allowing negative or fractional exponents would produce a non-polynomial expression.

2. A polynomial has highest nonzero term −4x7-4x^7. What is its degree and leading coefficient?

Degree −4-4 and leading coefficient 77
Degree 77 and leading coefficient 44
Degree 77 and leading coefficient −4-4
Degree −4-4 and leading coefficient −7-7

Degree $$7$$ and leading coefficient $$-4$$

Explanation

The degree is the exponent of the highest-degree nonzero term, while the leading coefficient is its numerical coefficient. Thus, −4x7-4x^7 gives degree 77 and leading coefficient −4-4.

3. Which expression is a polynomial function?

3x4−2x+7\frac{3}{x^4}-2x+7
3x4−2x+73x^4-2x+7
3x1/2−2x+73x^{1/2}-2x+7
3x−4−2x+73x^{-4}-2x+7

$$3x^4-2x+7$$

Explanation

The first expression has only nonnegative integer exponents and no variable in a denominator or radical. The other expressions contain a negative exponent, a fractional exponent, or a variable in the denominator.

4. Why is 2x−2+3x+52x^{-2}+3x+5 not a polynomial?

It contains a negative exponent
It contains a linear term
It contains real coefficients
It contains a nonzero constant term

It contains a negative exponent

Explanation

The term 2x−22x^{-2} has a negative exponent, which is not permitted in a polynomial. A nonzero constant term, a linear term, and real coefficients are all compatible with polynomial expressions.

5. For a polynomial with integer coefficients, what does the Rational Root Theorem require of a rational root written as pq\frac{p}{q} in lowest terms?

Both pp and qq divide the constant term
Both pp and qq divide the leading coefficient
pp divides the constant term and qq divides the leading coefficient
pp divides the leading coefficient and qq divides the constant term

$$p$$ divides the constant term and $$q$$ divides the leading coefficient

Explanation

The theorem identifies possible rational roots by taking the numerator from factors of the constant term and the denominator from factors of the leading coefficient. It produces candidates rather than proving that every candidate is an actual root.

6. For f(x)=6x3−5x2+4x−12f(x)=6x^3-5x^2+4x-12, which set contains all possible rational zeros generated by the Rational Root Theorem?

±1,±2,±3,±6,±12,±14,±15,±16\pm1,\pm2,\pm3,\pm6,\pm12,\pm\frac14,\pm\frac15,\pm\frac16
±1,±2,±4,±6,±12,±15,±25,±35\pm1,\pm2,\pm4,\pm6,\pm12,\pm\frac15,\pm\frac25,\pm\frac35
±1,±2,±3,±4,±6,±12,±16,±13,±23\pm1,\pm2,\pm3,\pm4,\pm6,\pm12,\pm\frac16,\pm\frac13,\pm\frac23
±1,±2,±3,±4,±6,±12,±12,±13,±23\pm1,\pm2,\pm3,\pm4,\pm6,\pm12,\pm\frac12,\pm\frac13,\pm\frac23

$$\pm1,\pm2,\pm3,\pm4,\pm6,\pm12,\pm\frac16,\pm\frac13,\pm\frac23$$

Explanation

The constant term is −12-12 and the leading coefficient is 66, so candidates have numerators from factors of 1212 and denominators from factors of 66. The listed set includes the resulting reduced fractions and integer candidates; the other sets omit valid combinations or use factors from the wrong coefficient.

7. When a polynomial f(x)f(x) is divided by x−cx-c, what does the Polynomial Remainder Theorem identify as the remainder?

The value of the constant term
The quotient evaluated at cc
The coefficient of the highest-degree term
The value f(c)f(c)

The value $$f(c)$$

Explanation

The theorem states that evaluating the polynomial at the divisor’s root, cc, gives the remainder. The quotient is a separate polynomial and is not generally equal to f(c)f(c).

8. What procedure finds the remainder when a polynomial is divided by x−cx-c using the Remainder Theorem?

Replace each occurrence of xx with x−cx-c and simplify
Substitute cc into the polynomial and evaluate the result
Factor the polynomial before identifying its constant term
Divide every coefficient by cc and add the quotients

Substitute $$c$$ into the polynomial and evaluate the result

Explanation

The required process is direct substitution of cc for xx, followed by evaluation of f(c)f(c). Polynomial division is not needed to obtain the remainder through this theorem.

9. According to the Factor Theorem, when is x−cx-c a factor of f(x)f(x)?

When f(c)=0f(c)=0
When f(c)f(c) equals the quotient
When f(c)=1f(c)=1
When f(c)f(c) has the highest degree

When $$f(c)=0$$

Explanation

The Factor Theorem says that x−cx-c is a factor precisely when evaluating the polynomial at cc gives zero. A nonzero value of f(c)f(c) indicates that the proposed linear expression is not a factor.

10. Which factor corresponds to the zero −1-1 of a polynomial?

x−1x-1
x2+1x^2+1
x+1x+1
−x+1-x+1

$$x+1$$

Explanation

A zero cc corresponds to the factor x−cx-c, so substituting c=−1c=-1 produces x−(−1)=x+1x-(-1)=x+1. The factor x−1x-1 instead corresponds to the positive zero 11.

11. For f(x)=x3−6x2+11x−6f(x)=x^3-6x^2+11x-6, which set contains all three tested values that produce a remainder of zero?

−3,3,6-3, 3, 6
1,2,61, 2, 6
1,2,31, 2, 3
−1,−2,−3-1, -2, -3

$$1, 2, 3$$

Explanation

Evaluating the polynomial at 11, 22, and 33 gives zero, so these values are zeros and their corresponding linear factors divide the polynomial. The other sets include values whose evaluations are nonzero.

Review with flashcards

Memorize the answers with 22 flashcards on Polynomial Functions and Theorems.

What is the general form of a polynomial expression in x of degree n?

It is anxn+an−1xn−1+⋯+a1x+a0a_nx^n+a_{n-1}x^{n-1}+\cdots+a_1x+a_0 with an≠0a_n \neq 0.

What must the degree n be in a polynomial expression?

A nonnegative integer.

What condition must the leading coefficient ana_n satisfy in a polynomial?

It must not be zero.

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