[填空题]
A farmer is going to fence k8bb9x tcy4;ur;0rbd xz(bg; tvv ws 8;xu9 rrl+2+wc3 (wrazdwo equal adjacent parcels of land. These parcels share one side (which also requires fencing;drzal+ v +rrw u2c(8 9sx3wwv) as shown in the following diagram. The farmer has only
80 metres of fence.
1. Write down the equation for the total length of the fence, 80 $\mathrm{~m}$ , in terms of x and y . y =
2. Write down the total area of both parcels of land in terms of x .
3. Find the maximum area, in $\mathrm{m}^{2}$ , of one parcel of land. ≈
