# Class 9th maths science group Chapter 4 Exercise 4.2

## Class 9th maths science group Chapter 4 Exercise 4.2

Class 9th maths science group Chapter 4 Exercise 4.2
10/26/2017 05:34:35 pm - notes - 9th - Mathematics Science Group - administrator

This series of lecture is about class 9th maths book exercise 4.2. You will get the lectures and notes about all the exercises of maths 9th, 10th, 11th, 12th. These lectures are related to Punjab Textbook Board PTB, Federal Board, Rawalpindi Board and all other educational boards of Punjab.

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This Lecture includes complete notes of Exercise 4.2 Algebraic Expressions and Algebraic Formulas from class 9th maths (science group) Punjab Text Book Board. For FBISE, RWPBISE and all other boards like Lahore Board, Sargodha Board etc.

In this Lecture you will go through following Topics: 1. Algebraic Formulae a) Using the Formulae i) (a+b)2 + (a-b)2 = 2(a2 + b2) and (a+b)2 - (a-b)2 = 4ab ii) (a + b + c)2 = a2 b2 c2 + 2ab + 2bc + 2ca iii) (a + b)3 = a3 + 3ab(a + b) + b3 (a - b)3 = a3 - 3ab(a - b) - b3 iv) a3 + b3 = (a + b)(a2 - ab + b2) a3 - b3 = (a - b)(a2 + ab + b2)