- In this question you must show detailed reasoning. Solutions relying on calculator technology are not acceptable.
$$f ( x ) = x ^ { 2 } ( 2 x + 1 ) - 15 x$$
- Solve
$$\mathrm { f } ( x ) = 0$$
- Hence solve
$$y ^ { \frac { 4 } { 3 } } \left( 2 y ^ { \frac { 2 } { 3 } } + 1 \right) - 15 y ^ { \frac { 2 } { 3 } } = 0 \quad y > 0$$
giving your answer in simplified surd form.