the sum of three number in AP is12 and sum of cubes is288.find the number
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◾️the sum of three number in AP is12 and sum of cubes is288.find the number
Let the numbers be a-d, a, a+d
By the given conditions,
(a-d)+(a)+(a+d) = 12
3a = 12
a = 4
(a-d)³ + a³ + (a+d)³ = 288
a³-d³-3a²d+3ad²+a³+a³+d³+3a²d+3ad² = 288
3a³+6ad² = 288
a³+2ad² = 96
4³+2(4)d² = 96
64+8d² = 96
8d² = 32
d² = 4
d = ±2
Hence the numbers are 2, 4, 6 (Using d = 2)
6, 4, 2 (Using d = -2)
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