A) -14
B) 7
C) 14
D) -7
Correct Answer: D
Solution :
Let e be the identity of Z. Then by given operation \[a*e=a+e+7\] \[\Rightarrow \] \[a=a+e+7\] \[[a*e=a]\] \[\Rightarrow \] \[e=-7\] Now inverse of \[-7\] \[{{(-7)}^{-1}}={{e}^{-1}}\] \[[e=-7]\] \[=e\] \[[{{e}^{-1}}=e]\] \[=-7\] \[[e=-7]\]You need to login to perform this action.
You will be redirected in
3 sec