A delivery drone flies along a straight line.

Step 1. Speeding up. $\tfrac12 \times 4\ \text{s} \times 6\ \text{m/s} = 12\ \text{m}$.

Step 2. Steady. $8\ \text{s} \times 6\ \text{m/s} = 48\ \text{m}$.

Step 3. The last part. The velocity falls by $8\ \text{m/s}$ in $4\ \text{s}$, $2\ \text{m/s}$ each second, so it reaches $0\ \text{m/s}$ after $3\ \text{s}$. Above the axis: $\tfrac12 \times 3\ \text{s} \times 6\ \text{m/s} = 9\ \text{m}$. Below: $\tfrac12 \times 1 \times 2 = 1\ \text{m}$, backwards.

Step 4. Totals. Displacement $12\ \text{m} + 48\ \text{m} + 9\ \text{m} - 1\ \text{m} = 68\ \text{m}$. Distance $12\ \text{m} + 48\ \text{m} + 9\ \text{m} + 1\ \text{m} = 70\ \text{m}$.