The value of (2.75)3 – (2.00)3 – (0.75)3 is__________?
A. 3 * 2.75 * 2.75 * 2.75
B. 3 * 2.00 * 2.00 * 2.00
C. 3 * 2.75 * 0.75 * 2.75
D. 4.5 * 2.75
Explanation:
(2.75)3 – (2.00)3 – (0.75)3
a3 + b3 + c3 = (a + b + c)(a3 + b3 + c3 – ab – bc – ca)
If a + b + c = 0 then a3 + b3 + c3 = 3abc
Hence 2.75 – 2.00 – 0.75 = 0
So, (2.75)3 – (2.00)3 – (0.75)3
= 3 * 2.75 * 2 * 0.75 = 3 * 1.5 * 2.75
= 4.5 * 2.75