[填空题]
A farmer is going to fja f/ 2hzg6ilu;tf)hv wl3ez.c ;8b 7gence two equal adjacent parcels of land. T /ho,e1rkd/ iphese parcels share one side (whi id,ep k//roh1ch also requires fencing) 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. ≈
