Mathematics 2022 JAMB Past Questions - Question 29:  If the binary operation * is defined by m*n = mn + m + n for any real number m and n, find the identity element under this operation.

Correct Answer

B

Explanation

To find the identity element under the binary operation *, we need to find a real number e such that for any real number m, m * e = e * m = m.Let's substitute m = e into the definition of the binary operation:m * e = me + m + eSince this should be equal to m for any real number m, we can equate the coefficients of e and the constant terms:me = 0m + e = mFrom the first equation, we can see that e = 0.Substituting e = 0 into the second equation, we get:m + 0 = mThis equation holds true for any real number m.Therefore, the identity element under the binary operation * is 0.