Example 20 - Chapter 2 Class 9 Polynomials
Last updated at Dec. 13, 2024 by Teachoo
Last updated at Dec. 13, 2024 by Teachoo
Example 20 Factorise : 8x3 + y3 + 27z3 – 18xyz 8x3 + y3 + 27z3 – 18xyz = (2x) 3 + y3 + (3z) 3 – 18xyz = (2x) 3 + y3 + (3z) 3 – 3(2x)(y)(3z) Using a3 + b3 + c3 – 3abc = (a + b + c)(a2 + b2 + c2 – ab – bc – ca) Putting a = 2x, b = y , c = 3z = (2x + y + 3z)[(2x)2 + y2 + (3z) 2 – (2x)(y) – (y)(3z) – (2x)(3z)] = (2x + y + 3z) (4x2 + y2 + 9z2 – 2xy – 3yz – 6xz)
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About the Author
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 and Computer Science at Teachoo