Polynomial Review · Lesson 1

Vocabulary & Degree.

Before you can operate on polynomials you have to read them: to look at a jumble of terms and instantly see how many terms there are, which powers appear, and which term is in charge. Degree is the single most important label, because the highest-degree term controls how the whole expression behaves.

By the end, you can

  • 1I can identify the terms, coefficients, and constant term of a polynomial.
  • 2I can find the degree of a single term (add the exponents) and the degree of a whole polynomial (the largest term-degree).
  • 3I can name a polynomial monomial / binomial / trinomial and state its leading coefficient.
  • 4I can write a polynomial in standard (descending) order and explain why that makes the degree obvious.
  • 5I can simplify first, then classify — never classifying an un-combined expression.
01 / CONCEPTS

The core ideas.

What a polynomial is made of

A term is a single product of a number and variable powers: 7x³, −2x, and 5 are all terms. The number multiplying the variable is the coefficient; in −2x the coefficient is −2. A term with no variable, like 5, is the constant term. A polynomial is terms joined by + or −.

Why it works

The +/− signs are the seams that stitch terms together. Read 3x² − 5x + 4 as (+3x²) + (−5x) + (+4): a term always carries its own sign. That one habit makes subtraction painless later.

Degree of a term

The degree of a term is the exponent on its variable. 7x³ has degree 3; 4x has degree 1 (the invisible exponent is 1); a nonzero constant like 5 has degree 0, because 5 = 5x⁰. The coefficient in front never changes the degree — only the exponent does, so −11x⁴ still has degree 4.

deg(11x4)=4\deg(-11x^4) = 4

Why it works

Degree measures how fast a term grows when x gets big. A degree-3 term eventually dwarfs a degree-2 term, which dwarfs a degree-1 term. That growth ranking is exactly why we sort by degree.

Degree of a polynomial and the leading term

The degree of a polynomial is the largest degree among its terms. The term owning that degree is the leading term, and its coefficient is the leading coefficient. In −2x⁴ + 9x² − x + 3 the degree is 4, the leading term is −2x⁴, and the leading coefficient is −2.

Why it works

When x is huge, the highest-degree term drowns out all the others, so it controls the polynomial's long-run personality. That is why it gets top billing — it literally leads.

Naming by number of terms

Count the terms AFTER combining like terms: 1 term = monomial (5x²), 2 terms = binomial (x + 7), 3 terms = trinomial (x² − 3x + 2). Four or more just get called a polynomial. Term count and degree are independent: x² − 3x + 2 is a degree-2 trinomial, and 4x³ is a degree-3 monomial.

Why it works

Count the terms, then measure the tallest. Term count is a headcount; degree is a height. A trinomial is not automatically degree 3.

Standard form (descending order)

Write terms from highest degree to lowest: 5 − 2x³ + x becomes −2x³ + x + 5. Standard form is not required for correctness, but it makes the degree, leading coefficient, and constant jump out and lines terms up for adding and subtracting.

Why it works

It is alphabetizing for math. Once everything is sorted tallest-first, the leading term is simply the one on the left and the constant is the one on the right.

02 / WORKED EXAMPLES

From easy to tricky.

EX 1easy

Classify 4x² − 7. Give its degree, leading coefficient, and name.

1

Count the terms

4x² and −7 → two terms → binomial.

2

Find the highest degree

The exponents are 2 and 0, so the degree is 2.

3

Read the leading parts

Leading coefficient is 4; the constant is −7.

EX 2easy

State the degree and the coefficient of the term −6x⁴.

1

Read the exponent for the degree

The exponent on x is 4, so the degree is 4.

2

Read the number in front

The coefficient is −6 (the minus is part of it) and does not affect the degree.

EX 3medium

Put 5 − 2x³ + x in standard form and name it.

1

Rank by degree

−2x³ (deg 3), x (deg 1), 5 (deg 0).

2

Write descending

−2x³ + x + 5.

3

Name it

Three terms → trinomial; degree 3 (cubic); leading coefficient −2.

EX 4medium

What is the degree of the constant polynomial 9? What about 0?

1

Rewrite 9

9 = 9x⁰, a nonzero term of degree 0, so the degree is 0.

2

Handle 0 separately

0 has no nonzero term at all, so there is nothing to measure — its degree is undefined.

EX 5challenge

After combining like terms, name and give the degree of 3x² + 5x − x² − 5x + 8.

1

Combine the x² terms

3x² − x² = 2x².

2

Combine the x terms

5x − 5x = 0, so they vanish.

3

Read the result

2x² + 8 → two terms → binomial, degree 2.

03 / COMMON TRAPS

Where students slip.

Trap

It has an x, so the degree is at least 1.

Fix

A constant has degree 0 (5 = 5x⁰). Don't invent a degree from a lone number, and don't assume every variable term is degree 1 — check the exponent.

Trap

Counting terms before combining like terms.

Fix

Always simplify first. 3x² + 5x − x² − 5x + 8 looks like five terms but is really the binomial 2x² + 8. Classify the true object, not the raw expression.

Trap

The degree is the exponent on whichever term is written first.

Fix

Degree is the maximum term-degree, not the leftmost. Sort to standard form first, or scan every term for the highest exponent.

Trap

The polynomial 0 has degree 0.

Fix

0 has NO degree (undefined) because it has no nonzero leading term to measure. A nonzero constant like 7 does have degree 0, since 7 = 7x⁰.

04 / QUIZ

Test yourself.

The Test

14 problems across three tiers. Auto-graded on submit. Hints and a full walkthrough on every question. Your work is saved on this device — sign in to keep it across devices.

0/14Answered
How to answerType just the value. Formatting won't trip you up — we ignore spaces, capital letters, commas, and subscript style, so t₁ = 5, d = 3 and t1=5,d=3 both count. For a list of numbers, separate them with commas (e.g. 3, 10, 17).
Core

Core (6)

C1

How many terms does 3x² − 5x + 4 have, and what is it called?

Need a hint?
  • Terms are the pieces joined by + or −.
  • Count the +/− separated pieces: 3x², −5x, +4.
C2

What is the degree of the term 7x³? (Enter a number.)

Need a hint?
  • The degree of a single term is its exponent.
C3

What is the degree of the term −11x⁴? (Enter a number.)

Need a hint?
  • The degree is the exponent on x.
  • The coefficient −11 does not change the degree.
C4

What is the leading coefficient of −2x⁴ + 9x² − x + 3?

Need a hint?
  • Find the highest-degree term first.
  • The highest degree is 4; read the number in front of x⁴.
C5

What is the degree of the constant term 5? Remember 5 = 5x⁰. (Enter a number.)

Need a hint?
  • A nonzero constant is a term of degree 0.
C6

Which is 5 − 2x³ + x written in standard (descending) form?

Need a hint?
  • Highest degree first, lowest last.
  • Degrees are 3, 1, 0 → −2x³, then x, then 5.
Apply

Apply (5)

A1

Simplify first, then classify: 3x² + 5x − x² − 5x + 8.

Need a hint?
  • Combine like terms before counting.
  • 3x² − x² = 2x²; 5x − 5x = 0; leaves 2x² + 8.
A2

Which statement is true?

Need a hint?
  • Separate 'how many terms' from 'how tall'.
  • x⁵ − x³ + 1 is a trinomial of degree 5.
A3

What is the degree of the polynomial 0?

Need a hint?
  • Degree needs a nonzero leading term to measure.
  • 0 has no nonzero term; 7 does (7 = 7x⁰, degree 0).
A4

State the leading coefficient of −x³ + 6x² − 9. (Enter a number.)

Need a hint?
  • The highest-degree term is −x³.
  • The invisible coefficient on −x³ is −1.
A5

x⁵ − x³ + 1 is best described as:

Need a hint?
  • Count terms, then find the highest exponent.
Extension

Extension (3)

E1

The polynomial ax³ + 4x² − x + a is said to have degree 2. What is a, and what is the resulting polynomial?

Need a hint?
  • For the degree to drop to 2, the x³ term must disappear.
  • That needs a = 0 — and then the constant a is 0 too.
E2

Why does 0 have no degree while 7 has degree 0?

Need a hint?
  • Degree is read off the leading (nonzero) term.
E3

Combine like terms in 2x² − 2x² + 7x, then enter the degree of the result. (Enter a number.)

Need a hint?
  • Simplify before reading the degree.
  • 2x² − 2x² = 0, leaving 7x.