Which of the following expressions CANNOT have a negative value
Choose the correct choice from the following choices.
A) |a + b| – |a – b|
B) |a + b| – |a|
C) |2a + b| – |a + b|
D) a^2 + b^2 |+ 2|ab|
E) |a^3 + b^3| – a – b
Whenever you are required to find if the equation is a perfect square or not, try to bring everything in the form of a perfect square as they are always positive.   Of the given options, only option D can be written in from of a perfect square.   a^2+b^2+2|ab| = |a|^2 + |b|^2 + 2|a||b| = (|a| +|b|)^2.   This will always be positive.   Correct Option: a^2 + b^2 |+ 2|ab|
<result>D</result>
Which of the following expressions CANNOT have a negative value