2[(620)² + (580)²] - (620 + 580)² = ?

Expression: $$2[(620)^2 + (580)^2] - (620 + 580)^2$$​​
Formula Used:
​$$2(a^2 + b^2) - (a + b)^2 = (a - b)^2$$​​
Solution:
Let a = 620 and b = 580.
The given expression is in the form of $$2(a^2 + b^2) - (a + b)^2.$$​​
​$$2[(620)^2 + (580)^2] - (620 + 580)^2$$​​
= $$(620 - 580)^2$$​​
= $$40^2$$​​
= 1600
Final Answer
So the correct answer is (d)