w = var('w')
A(w) = w*(70-w)
F(w) = 825
p1 = plot(F,w,0,70,color='red')
p2 = plot(A,w,0,70)
p3 = point((15,A(15)),color='black')
p4 = text('(15,825)',(12.5,880),color='black')
p5 = point((55,A(15)),color='black')
p6 = text('(55,825)',(57.3,880),color='black')
p7 = point((35,A(35)),color='black')
p8 = text('(35, 1225)',(33,1225),color='black')
P = p1+p2+p3+p4+p5+p6
show(P)
P.save('graph_with_range.pdf')