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Identity VIII
Identities VIII You are here
Ex 2.4, 9 (i)
Ex 2.4, 10 (i) Important Deleted for CBSE Board 2025 Exams
Ex 2.4,12 Important
Ex 2.4,13
Ex 2.4, 14 (i)
Example 20 Important
Chapter 3 Class 9 Coordinate Geometry→
Chapter 2 Class 9 Polynomials
Concept wise
- Definition
- Value of a polynomial at a given point
- Verifying Zeroes of a polynomial
- Finding Zeroes of a polynomial
- Remainder Theoram
- Check if factor
- Factorisation by middle term
- Factorisation by factor formula
- Factorizing cubic equation
- Identity I - IV
- Identity V
-
Identity VIII
Last updated at April 16, 2024 by Teachoo
Identity VII is
- a 3 + b 3 + c 3 − 3abc = (a + b + c) (a 2 + b 2 + c 2 − ab − bc − ac)
Lets take an example
a 3 + b 3 + c 3 − 3abc = (a + b + c) (a 2 + b 2 + c 2 − ab − bc − ac)
2 3 + 3 3 + 4 3 – 3(2)(3)(4)
= (2 + 3 + 4) (2 2 + 3 2 + 4 2 – (2)(3) – (3)(4) – (4)(2))
8 + 27 + 64 – 72 = (9) (4 + 9 + 16 – 6 – 12 – 8)
99 – 72 = (9) (29 – 26)
27 = (9) (3)
27 = 27
If a + b + c = 0
Then,
a 3 + b 3 + c 3 − 3abc = (a + b + c) (a 2 + b 2 + c 2 − ab − bc − ac)
a 3 + b3 + c 3 − 3abc = (0) (a 2 + b 2 + c 2 − ab − bc − ac)
a 3 + b 3 + c 3 − 3abc = 0
a 3 + b 3 + c 3 = 3abc
Check Algebra Formulas for full list of formulas
Next: Ex 2.4, 9 (i) → Go Ad-free
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Made by
Davneet Singh
Davneet Singh has done his B.Tech from Indian Institute of Technology, Kanpur. He has been teaching from the past 14 years. He provides courses for Maths, Science, Social Science, Physics, Chemistry, Computer Science at Teachoo.
