Solve this: â ‹Q27 If a + b + 2c = 0 , prove that a3 + b3 - Maths - Expansions

Question

Solve this:

â€‹Q27 If a + b + 2c = 0 , prove that
a3 + b3 + 8c3 = 6abc

â€‹Q28 If a + b + c = 0, then find the value of a
2 b c + b 2 c a + c 2 a b

Q29 If x + y = 4, then find the value of x3 +
y3 + 12 xy – 64

Q30 Without actually calculating the cubes, find the values of
:

(i) (27)3 + (–17)3 +
(–10)3 (ii) (–28)3 +
(15)3 + (13)3

Brijendra Pal · Accepted Answer

Hi, 27:We know that if x+y+z = 0 then x3+y3+z3= 3xyzhere x = a, y = b , z = 2c so putting these values hence , a3+b3+2c3= 3×a×b×2ca3+b3+8c3= 6abc Please post single query in a thread