Find the sum and difference of the identity function and the modulus function.

Explanation

identity function is` f(x)=x, `modulus function is `f(x)=∣x∣`


sum of them `=x+∣x∣`


that is equal to
`2x` if` x>0 `and 0 if `x<0`


product of them is `x xx ∣x∣`
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