reset
set border
set xtics 1
set ytics 1
set xzeroaxis lt 9 lw 5
set yzeroaxis lt 9 lw 5
set style line 1 lt 1 lw 3
set style line 2 lt 3 lw 5
set style line 3 lt 10 lw 6
set style line 4 lt 12 lw 3
set style line 5 lt 9 lw 1
set grid ls 5
show grid
set xrange [-7:7]
set yrange [-10:10]
set samples 1000
set key on
f(x)=x+2
g(x)=x**2-9
h(x)=f(x)/g(x)
i(x)=x-7
j(x)=sqrt(16-x**2)
k(x)=i(x)/j(x)
plot h(x) ls 1,k(x) ls 2
# plot f(x) ls 1,g(x) ls 2, h(x) ls 3
# plot i(x) ls 1,j(x) ls 2, k(x) ls 3