Search SchoolNGR

Tuesday, 30 June 2026
Register . Login

The binary operation * is defined on the set of R, of real numbers by \(x * y = 3x + 3y ...

The binary operation * is defined on the set of R, of real numbers by \(x * y = 3x + 3y - xy, \forall x, y \in R\). Determine, in terms of x, the identity element of the operation.
Take Free Practice Test On 2026 JAMB UTME, Post UTME, WAEC SSCE, GCE, NECO SSCE
  • A \(\frac{2x}{x - 3}, x \neq 3\)
  • B \(\frac{2x}{x + 3}, x \neq -3\)
  • C \(\frac{3x}{x - 3}, x \neq 3\)
  • D \(\frac{3x}{x + 3}, x \neq -3\)
Correct Answer: Option A
Explanation:
From the rules of binary operation, \(x * e = x\)
\(\implies x * e = 3x + 3e - xe = x\)
\(3e - xe = x - 3x = -2x\)
\(e = \frac{2x}{x - 3}, x \neq 3\)

Share question on: