Paper 22 Q14IGCSE 0580 May/June 2023

Question

14 f(x)=5x+2 Find f^{-1}(x).

This question tests your ability to find the inverse function of a linear function. Finding inverse functions is important because it helps you understand how to 'undo' a function and work backwards from an output to find the input.

Step-by-Step Solution

Key Takeaway

To find an inverse function, swap x and y, then make y the subject of the equation.

Common Mistakes

Forgetting to swap x and y variables, which means you haven't actually found the inverse function
Making algebraic errors when rearranging, such as dividing only part of the expression by 5 instead of the whole numerator

Exam Tip

Always check your inverse function by substituting it back into the original function - you should get x as your final answer.

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