Solution:
Given:
a = 355
b = 356
c = 357
Formula used:
a3 + b3 + c3 - 3abc = (21)×(a+b+c)×[(a – b)2 + (b – c)2 + (c – a)2]
Calculations:
a3 + b3 + c3 - 3abc = (21)×(355+356+357)×[(355 – 356)2 + (356 – 357)2 + (357 – 355)2]
⇒ (21)×(1068)×(1+1+4)
⇒ 534×6
⇒ 3204
∴ The value of a3 + b3 + c3 - 3abc is 3204