if f(x)=2x-9, find f(p) and f(x+h)
\(f(x)=2x-9\\\\f(p)\to substitute\ x=p\\\\f(p)=2p-9\\\\f(x+h)\to substitute\ x=x+h\\\\f(x+h)=2(x+h)-9=2x+2h-9\)
\(f(p)=2p-9\\ f(x+h)=2(x+h)-9=2x+2h-9\)
