Mathematics - Can you explain the steps to working out the answer?

Step 1 — Identify the polynomial and confirm it is degree 3. Step 2 — Use the factor theorem to find one root by testing values. Step 3 — Divide the polynomial to get a quadratic factor. Step 4 — Factorise the quadratic to find all roots. Step 5 — Find the derivative and set it to zero to find turning points. Step 6 — Determine the y-intercept and sketch the curve.