Example 1
Simplify.

a, b


If each variable is nonnegative (not a negative number),
If each variable could be positive or negative (deleting the restriction “If each variable is nonnegative”), then absolute value signs are placed around variables to odd powers.

e
If each variable is nonnegative,

f
If each variable is nonnegative,
If each variable could be positive or negative, then you would write
If each variable could be positive or negative, you would write
If each variable could be positive or negative, you would write

i
If each variable is nonnegative,

j
If each variable is nonnegative,