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Letastbe a binary operation on N defin...

Let`ast`be a binary operation on `N` defined by `a ast b=a+b+10` for all `a ,\ b in N` . The identity element for `ast` in `N` is

A

(a) `-10`

B

(b) `0`

C

(c) `10`

D

(d) Does not Exist

Text Solution

Verified by Experts

The correct Answer is:
(a) `-10`
Let
`e=` identity
`a o e= e o a=a, a forall N`
`a ast e =a`
`a+e+10=a`
`e+10=0`
`e=-10`

Hence, the value of `e=-10`
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