Class 9 Maths Chapter 2, Introduction to Linear Polynomials, is the algebra chapter that follows coordinates in Ganita Manjari. It starts from a shopkeeper’s problem (x red boxes of 4 pens and y blue boxes of 5 pencils, plus 3 free pens, give 4x + 5y + 3) and ends with straight-line graphs: by the last section you can read the slope and y-intercept of y = ax + b and tell linear growth from linear decay.
What Class 9 Maths Chapter 2 Covers
2.1 Introduction revises algebraic expressions, terms and coefficients through everyday counting problems, such as working out the total number of pens and pencils in Raju’s boxes.
2.2 Linear Polynomials defines a univariate polynomial and its degree (x² + 5x + 3 has degree 2, 3y³ – 4y² + 5 has degree 3) and singles out the degree-one case, 2x + 3 or 5 – 4y, as a linear polynomial.
2.3 Exploring Linear Patterns and 2.4 Linear Growth and Linear Decay look at sequences whose consecutive terms differ by a constant, such as a growing pattern of square tiles, and separate quantities that rise by a fixed amount in equal intervals from those that fall by a fixed amount.
2.5 Linear Relationships and 2.6 Visualising Linear Relationships connect two variables through y = ax + b and plot them on the coordinate plane from Chapter 1. The slope a and the y-intercept b are named and explained, and the special case b = 0 gives a line through the origin. This is the longest section of the chapter, running over nine pages of graphs.
Exercises in Chapter 2
- Exercise Sets 2.1 to 2.6 follow each section: writing expressions for word problems, finding degrees, continuing linear patterns, separating growth from decay, and drawing and reading straight-line graphs.
- End-of-Chapter Exercises mix all of these, ending with a one-page chapter summary that lists every definition from polynomial to y-intercept.
Read Class 9 Maths Chapter 2 Online
More Chapters
- Previous: Chapter 1: Orienting Yourself: The Use of Coordinates
- Next: Chapter 3: The World of Numbers
- Hindi medium: Class 9 Maths Chapter 2 PDF in Hindi
- All Maths chapters and the other Class 9 books: Class 9 NCERT books 2026-27
FAQ
What is a linear polynomial in Class 9 Maths Chapter 2?
A polynomial of degree one in its variable, such as 2x + 3 or 5 – 4y. The chapter contrasts it with higher-degree polynomials like x² + 5x + 3.
What do a and b mean in y = ax + b?
a is the slope of the line and b is the y-intercept, the point where the line cuts the y-axis. When b = 0 the line y = ax passes through the origin.