If x = 222, y = 223, z = 225, then the value of x3 + y3 + z3 - 3xyz is?
A. 4590
B. 4690
C. 4950
D. 4960
Answer: Option B
Solution (By Examveda Team)
$${x^3} + {y^3} + {z^3} - 3xyz$$$$ = \frac{1}{2}\left( {x + y + z} \right)$$ $$\left[ {{{\left( {x - y} \right)}^2} + {{\left( {y - z} \right)}^2} + {{\left( {z - x} \right)}^2}} \right]$$
$$ = \frac{1}{2}\left( {222 + 223 + 225} \right)$$ $$\left[ {{{\left( {222 - 223} \right)}^2} + {{\left( {223 - 225} \right)}^2} + {{\left( {225 - 222} \right)}^2}} \right]$$
$$\eqalign{ & = \frac{1}{2}\left( {670} \right)\left( {1 + 4 + 9} \right) \cr & = \frac{1}{2} \times 670 \times 14 \cr & = 4690 \cr} $$
only asked x3+y3+z3 ; but in answer extra - 3xyz added