[填空题]
A farmer is going to fence two equal adjacent parcels our5kz)ec7h *3g m. w.4evjgtq,epckt;0ks v6 f lblo9,b djx) v-y- fhrvf2d 9z+and. These parcels share one side (which also requires fr--x,vd ybfj ) l+bvzohd299 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. ≈
