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

- g
- If each variable is nonnegative,

If each variable could be positive or negative, you would write

- h
- If each variable is nonnegative,

If each variable could be positive or negative, you would write

- i
- If each variable is nonnegative,
- j
- If each variable is nonnegative,