Find a^3+b^3+c^3-3abc if a+b+c=9 and a^2 + b^2 + c^2=35
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8
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duazainab417:
What about the third step? How is it done?
35 is subtracted grom both sides....So 2(ab+bc+ca) = 46
now 2 is divided from both sides.....So ab+bc+ca = 23
How did 23 come?
46/2
I need one more help
sure, go ahead
i have asked one more question.. could u please check that and answer that too
answering another question.....in a minute
Thanks alot
Answered by
5
Answer:
108
Step-by-step explanation:
A+b+c= 9 and a 2 + b 2 +c 2 = 35, find the value of a 3 +b 3 +c 3 -3abc
Consider the formula - a³+b³+c³- 3abc = (a+b+c) (a²+b²+c²-(ab+bc+ca))
We have to find ab+bc+ca
given a+b+c = 9
Squaring on both sides we get,
(a+b+c)² = 9²
a²+b²+c² + 2(ab+bc+ca) = 81
2 (ab+bc+ca) = 46
ab + bc + ca = 23
Now, a³+b³+c³-3abc = (a+b+c) (a²+b²+c²-(ab+bc+ca))
Putting the values we get
9 (35 - 23)
9 x 12
108
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