Request a call back

Join NOW to get access to exclusive study material for best results

CBSE Class 9 Answered

if a+b+c = 9 and ab+bc+ca = 23 then a cube + b cube + c cube- 3abc=
Asked by RUDRA YADAV | 15 Sep, 2013, 08:33: PM
Expert Answer

a3+b3+c3- 3abc = (a+b+c) (a2+b2+c2-ab-bc-ca)

a+b+c= 9 (given)

ab+ bc + ca = 23 (given)

So, a3+b3+c3- 3abc = 9 (a2+b2+c2- 23)            ... (1)

 

(a+b+c)2= a2+b2+c2+ 2ab+ 2bc+ 2ca

92= a2+b2+c2+ 2(ab+bc+ca)

81= a2+b2+c2+ 2(23)

81 = a2+b2+c2+ 46

a2+b2+c2= 35

 

From (1), we get,

a3+b3+c3- 3abc = 9 (35-23) = 108

Answered by | 15 Sep, 2013, 10:59: PM
CBSE 9 - Maths
Asked by lovebagri455 | 14 Jul, 2022, 04:56: PM
ANSWERED BY EXPERT
CBSE 9 - Maths
Asked by avani2713 | 08 Jul, 2022, 01:52: AM
ANSWERED BY EXPERT
CBSE 9 - Maths
Asked by yeshudarsh | 05 Jul, 2022, 06:38: PM
ANSWERED BY EXPERT
CBSE 9 - Maths
Asked by janardanjc1982 | 28 Jun, 2022, 08:21: PM
ANSWERED BY EXPERT
CBSE 9 - Maths
Asked by meghapatel29121998 | 23 Jun, 2022, 10:08: PM
ANSWERED BY EXPERT
CBSE 9 - Maths
Asked by dpsvijender | 21 Jun, 2022, 10:37: AM
ANSWERED BY EXPERT
CBSE 9 - Maths
Asked by mmansingh949 | 21 Jun, 2022, 09:54: AM
ANSWERED BY EXPERT
CBSE 9 - Maths
Asked by vandanagarwal28 | 18 Jun, 2022, 05:57: PM
ANSWERED BY EXPERT
CBSE 9 - Maths
Asked by sumithra.suresh1 | 18 Jun, 2022, 05:15: PM
ANSWERED BY EXPERT
CBSE 9 - Maths
Asked by vandanagarwal28 | 17 Jun, 2022, 03:53: PM
ANSWERED BY EXPERT
×