Question

Let \( f(x) = \dfrac{ax + b}{cx + d} \). Then \( f(x) = x \), provided that:

• A. \(d=-a\)
• B. \(d=a\)
• C. \(a=b=1\)
• D. a=b=c=d=1

Hint:

For identities, equate coefficients of like powers of x.

Answer 1

The Correct Option is B