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01
LESSON 01 · CLASS 9 MATHEMATICS (NCERT)

Polynomials in One Variable & Zeroes

Master polynomial terms, coefficients, degree of polynomials, linear/quadratic/cubic classification, and finding zeroes p(c) = 0.

01 · DEFINITION & DEGREE

What is a Polynomial?

An algebraic expression of the form p(x) = aₙxⁿ + aₙ₋₁xⁿ⁻¹ + ... + a₁x + a₀, where non-negative integers n represent exponent powers, is called a polynomial in variable x.

CLASSIFICATION BY DEGREE

Degree of Polynomial

• Constant Polynomial (Degree 0): p(x) = 5 (Non-zero constant polynomial degree is 0).

• Linear Polynomial (Degree 1): p(x) = 2x + 3

• Quadratic Polynomial (Degree 2): p(x) = x² - 4x + 4

• Cubic Polynomial (Degree 3): p(x) = x³ - 3x² + 3x - 1

02 · ZEROES OF A POLYNOMIAL

Finding Value & Zeroes p(x) = 0

A real number c is called a zero of a polynomial p(x) if p(c) = 0.

SOLVED EXAMPLE

Find the zero of the polynomial p(x) = 2x + 5

Set p(x) = 0:

2x + 5 = 0
2x = -5 ⟹ x = -5/2

Hence, -5/2 is the zero of the linear polynomial p(x).