The Value of ( 6 + 10 - 21 - 35 ) × ( 6 - 10 + 21 - 35 ) = ?

Answer: Option D

($$\sqrt{6}$$  + $$\sqrt{10}$$  - $$\sqrt{21}$$  - $$\sqrt{35}$$) × ($$\sqrt{6}$$  - $$\sqrt{10}$$  + $$\sqrt{21}$$  - $$\sqrt{35}$$)
= {($$\sqrt{6}$$  - $$\sqrt{35}$$) + ($$\sqrt{10}$$  - $$\sqrt{21}$$)} × {($$\sqrt{6}$$  - $$\sqrt{35}$$) - ($$\sqrt{10}$$  - $$\sqrt{21}$$)}
= ($$\sqrt{6}$$  - $$\sqrt{35}$$)² - ($$\sqrt{10}$$  - $$\sqrt{21}$$)²
= 6 + 35 - 2$$\sqrt{210}$$  - 10 - 21 + 2$$\sqrt{210}$$
= 41 - 31
= 10