2026 AHS P2 Q4

The cubic polynomial \(\mathrm{f}(x)\) is such that the roots of \(\mathrm{f}(x)=0\) are \(-2\), \(1\) and \(k\). It is given that \(\mathrm{f}(x)\) has a remainder of \(-24\) when divided by \(x\), and a remainder of \(-18\) when divided by \((x+1)\).

1. Find the value of \(k\) and an expression for \(\mathrm{f}(x)\).[5]
2. Hence, or otherwise, solve \(\mathrm{f}(1-2y)=0\).[2]