## Algebra 2 (1st Edition)

Let $x$ be the number of desktop computers bought ($0\leq x\leq80$). Then the number of laptops bought is: $80-x$. Then the amount spent if we buy $x$ desktop computers is: $f(x)=x\cdot900+(80-x)\cdot1550=900x+124000-1550x=124000-650x$. Thus if $65$ choose desktops, the cost is: $f(65)=124000-650\cdot65=81750$