ok so here is what I have worked out so far...
Luxury Houses = x
Basic Houses = y
(300x + 5y) + (150y + 10x) = 6000m2 i'm not too sure if this is correct
I also came to the conclusion for graph purposes the answer might be y= -0.5x + 10 ?
I also know the most profit is £280,000 with 10 luxury houses and 20 basic.