A binary operation * is defined on the set of real numbers, R, by \(x * y = x + y - xy\). If the identity element under the operation * is 0, find the inverse of \(x \in R\).

A.

\(\frac{-x}{1 - x}, x \neq 1\)

B.

\(\frac{1}{1 - x}, x \neq 1\)

C.

\(\frac{-1}{1 - x}, x \neq 1\)

D.

\(\frac{x}{1 - x}, x \neq 1\)

Correct answer is A

\(x * y = x + y - xy\)

Let \(x^{-1}\) be the inverse of x, so that

\(x * x^{-1} = x + x^{-1} - x(x^{-1}) = 0\)

\(x + x^{-1} - x(x^{-1}) = 0 \implies x(x^{-1}) - x^{-1} = x\)

\(x^{-1}(x - 1) = x \implies x^{-1} = \frac{x}{x - 1}\)

= \(\frac{x}{-(1 - x)} = \frac{-x}{1 - x}, x \neq 1\)