Functions and Graphs

y varies directly as \(x^2\). When \(x=3\), \(y=45\). Find

1. the formula connecting \(y\) and \(x\);

   [2]

2. \(y\) when \(x=-4\);

   [1]

3. the positive value of \(x\) when \(y=80\).

   [1]