If the binary operation ast is defined by m ast... - JAMB Mathematics 1992 Question
If the binary operation \(\ast\) is defined by m \(\ast\) n = mn + m + n for any real number m and n, find the identity of the elements under this operation
A
e = 1
B
e = -1
C
e = -2
D
e = 0
correct option: b
m (\ast) n = mn + m + n
m (\ast) e = me + m + e, e (\ast) m = e
∴ me + m + e, m(e + 1)e - e = 0
e + 1 = 0
∴ e = -1
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