set zeroaxis
set xrange[-5:2]
set yrange[-10:25]
set nokey
set grid
set xtics('$x_0$' -3,'$x_0+h$' 0)
set ytics('$f(x_0)$' 5,'$f(x_0+h)$' 20)
set label '$_{A[x_0,f(x_0)]}$' at -3,4      
set label '$_{B[x_0+h,f(x_0+h)]}$' at 0,19
set xlabel '$x$'
set ylabel '$f(x)$'
plot -x**2+2*x+20,5*x+20
set terminal postscript eps
set output "c:\\uno.eps"
replot