Polynomial Operations

What’s a Polynomial?

An expression with variables and coefficients, using only:

  • Addition and subtraction
  • Multiplication
  • Non-negative integer exponents (0, 1, 2, 3, …)

Degree

The degree is the highest exponent in the polynomial.


What’s NOT a Polynomial

  • 1x\frac{1}{x} — negative exponent (x1x^{-1})
  • x\sqrt{x} — fractional exponent (x1/2x^{1/2})
  • 2x2^x — variable in the exponent

Adding and Subtracting

Combine like terms (same variable and exponent).

(3x2+2x)+(5x2x)=8x2+x(3x^2 + 2x) + (5x^2 - x) = 8x^2 + x


Multiplying

Distribute each term to every term in the other polynomial.

(x+2)(x+3)=xx+x3+2x+23=x2+3x+2x+6=x2+5x+6\begin{aligned} (x + 2)(x + 3) &= x \cdot x + x \cdot 3 + 2 \cdot x + 2 \cdot 3 \\ &= x^2 + 3x + 2x + 6 \\ &= x^2 + 5x + 6 \end{aligned}