A worksheet that contains equations with composite functions and includes when a composite is equal to an inverse. All the equations will develop into quadratics that can be factorised. For this reason, this worksheet is excellent for higher GCSE students who want practice with their algebra, as well as with functions. The first questions are reasonably straightforward and typical of GCSE. The last row is particularly challenging and great preparation for students aiming for level 8 and 9.