16. Ifa + b + c = 15 and a2 + b2 + c = 83, find the value of a3 + b3 + c3 - 3abc.
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Answered by
1
Step-by-step explanation:
a + b + c = 15
Doing square both side
(a + b + c)² = (15)²
a²+b²+c²+2(ab+bc+ca) = 225
83 + 2(ab+bc+ca) = 225
2(ab+bc+ca) = 225-83 = 142
ab+bc+ca = 71
Now ,
a³ + b³ + c³ - 3abc
= (a+b+c) {a²+b²+c² - (ab+bc+ca)}
= 15 { 83 - 71 }
= 15 × 12
= 180
It's the solution
I hope it helps you .
Answered by
1
Step-by-step explanation:
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