CBSE Class 9 Answered
Please Help Experts,
Asked by prakash.sanyasi | 29 Dec, 2019, 08:35: AM
Expert Answer
(x+y+z)(x²+y²+z²-xy-yz-zx)=x³+y³+z³-3xyz.....(1)
Now,
(a-b-c)(a²+b²+c²+ab-bc+ca)
=[a+(-b)+(-c)][a²+(-b)²+(-c)²-a(-b)-(-b)(-c)-(-c)a]
= a³+(-b)³+(-c)³-3a(-b)(-c)
= a³-b³-c³-3abc.......From (1)
Therefore,
(a-b-c)(a²+b²+c²+ab-bc+ca)=a³-b³-c³-3abc
Now,
(a-b-c)(a²+b²+c²+ab-bc+ca)
=[a+(-b)+(-c)][a²+(-b)²+(-c)²-a(-b)-(-b)(-c)-(-c)a]
= a³+(-b)³+(-c)³-3a(-b)(-c)
= a³-b³-c³-3abc.......From (1)
Therefore,
(a-b-c)(a²+b²+c²+ab-bc+ca)=a³-b³-c³-3abc
(98)³ = (100-2)³
identity=(a-b)³=a³-3a²b+3ab²-b³
a=100
b=2
(100-2)³=100³-3(100)²(2)+3(100)(2)²-2³
=1000000-8-60000+1200
=941192
hence (98)³=9,41,192
Answered by Yasmeen Khan | 29 Dec, 2019, 12:28: PM
CBSE 9 - Maths
Asked by mmansingh949 | 21 Jun, 2022, 09:54: AM
ANSWERED BY EXPERT
CBSE 9 - Maths
Asked by dalalvansh4 | 02 Jun, 2022, 07:03: PM
ANSWERED BY EXPERTCBSE 9 - Maths
Asked by s1044kasturipriyambada026582 | 27 May, 2022, 12:02: PM
ANSWERED BY EXPERTCBSE 9 - Maths
Asked by abilash8b | 06 Jan, 2022, 12:27: PM
ANSWERED BY EXPERTCBSE 9 - Maths
Asked by chintanasati.04ff2 | 13 Jul, 2021, 05:01: PM
ANSWERED BY EXPERTCBSE 9 - Maths
Asked by nilayraj07 | 07 Feb, 2021, 07:55: PM
ANSWERED BY EXPERTCBSE 9 - Maths
Asked by mayureshwani91.9dgatl | 04 Nov, 2020, 06:55: PM
ANSWERED BY EXPERTCBSE 9 - Maths
Asked by gulnaazkhatoon50328 | 05 Jun, 2020, 06:40: PM
ANSWERED BY EXPERT