If (a+b)=2,(b+c)=1, and (c+a)=3 then find a3+b3+c3 ?
(a) 3
(b) 1
(c) 8
(d) 9
Sol:
a + b = 2
b + c = 1
c + a = 3
(a + b + c) = 3
Cube both sides
a³ + b³ + c³ + 3(a + b) (b + c) (c + a) = 27
a³ + b³ + c³ = 27 – 18
= 9
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