A binary operation ⊗ defined on the set of integers is such that m⊗n = m + n + mn for all integers m and n. Find the inverse of -5 under this operation, if the identity element is 0
- A.
–^{5}/_{4} - B.
–^{5}/_{6} - C.
zero - D.
5
Correct Answer: Option A
Explanation
(m otimes n = m + n + mn)
Let the inverse of -5 be n).
(therefore -5 otimes n = 0)
(-5 + n + (-5n) = 0)
(n – 5n = 5 implies -4n = 5)
(n = -frac{5}{4})