Deciding between a power law and an exponential law

Two readings of a quantity \(y\) are \(y=6\) when \(x=1\) and \(y=48\) when \(x=4\). One scientist proposes \(y=ax^n\); another proposes \(y=cb^x\), where \(a\), \(n\), \(b\) and \(c\) are positive constants.

1. Find \(a\) and \(n\) for the first law, and \(b\) and \(c\) for the second, so that each fits both readings exactly.[4]
2. A third reading is \(y=162\) when \(x=9\). Decide which law the data support, and state which pair of variables would then give a straight-line graph through all three points.[3]