CAT Quantitative Aptitude Questions | CAT Algebra - Functions questions

The question is about Invertible Functions. We need to find out the value of the x for which the function and the inverse function is equal. Functions is a simple topic which involves a lot of basic ideas. Make sure that you a get of hold of them by solving these questions. A range of CAT questions can be asked based on this simple concept of Functions questions in the CAT Exam. Make sure you practice a lot of questions in CAT Functions Algebra to push your CAT preparation in the right direction. Functions as an idea is a fabulous idea if one can wrap their head around it the right way, and it has been one of the staple ideas tested by the CAT exam historically.

Question 19: If f(x) = \\frac{(x + 6)}{(x+2)}\\). Find the value of x for which f(x) = f^-1(x)?

1. -3
2. 2
3. Both A and B
4. None of these

Explanatory Answer

Method of solving this CAT Question from CAT Algebra - Functions: When will we have an invertible function ?

f(x) = f^-1(x) when f(x) = x

=> \\frac{(x + 6)}{(x+2)}\\) = x
=> x + 6 = x² + 2x
=> x² + x – 6 = 0
=> (x+3) (x-2) = 0
=> x = -3, 2

The question is "Find the value of x for which f(x) = f^-1(x)?"

Hence the answer is "Both A and B"

Choice C is the correct answer.