9. The curve with equation \(y = 2 x ^ { \frac { 3 } { 2 } } - 8 x ^ { \frac { 1 } { 2 } }\) has a minimum at the point \(A\).
- Find \(\frac { \mathrm { d } y } { \mathrm {~d} x }\).
- Find the \(x\)-coordinate of \(A\).
The point \(B\) on the curve has \(x\)-coordinate 2 .
- Find an equation for the tangent to the curve at \(B\) in the form \(y = m x + c\).