Class 9 · Mathematics · New NCERT
Chapter 2: Introduction to Linear Polynomials
Chapter 2 introduces polynomials in one variable and focuses on linear polynomials (degree 1). Starting from everyday situations such as buying boxes of pens, fencing a garden and fixed-plus-per-use charges, the chapter explains terms, coefficients, variables and degree, treats a polynomial as an input-output process, and uses linear patterns to model linear growth and linear decay. It then shows how to find the linear relationship y = ax + b from two data points and how to draw its graph, where a is the slope and b is the y-intercept.
Topics covered
- Algebraic expressions, terms, coefficients and variables
- Polynomials in one variable and their degree (constant, linear, quadratic, cubic)
- Linear polynomials and linear equations
- Polynomials as input-output processes (functions)
- Linear patterns and the nth term
- Linear growth and linear decay
- Finding the linear relationship y = ax + b from two points
- Graphing linear relationships: slope, y-intercept and parallel lines