Search SchoolNGR

Tuesday, 03 March 2026
Register . Login

An operation * is defined on the set of real numbers by a*b = a + b + 1. If the ...

An operation * is defined on the set of real numbers by a*b = a + b + 1. If the identity elements is -1, find the inverse of the element 2 under *.
Take Free Practice Test On 2026 JAMB UTME, Post UTME, WAEC SSCE, GCE, NECO SSCE
  • A 4
  • B Zero
  • C -2
  • D -4
Correct Answer: Option D
Explanation:
By definition a*b = a + b + 1.
Let the inverse of the element 2 be x,
Therefore 2*x = -1
i.e. 2 + x + 1 = -1
3 + x = -1
x = -1 - 3
x = -4

Share question on: