reset
set border
set xtics 1
# set ytics 1
set grid
set xzeroaxis lt 9 lw 2
set yzeroaxis lt 9 lw 2
set style line 1 lt -1 lw 3
set style line 2 lt 5 lw 3
set style line 3 lt 12 lw 3
set xrange [-6:6]
set yrange [-120:120]
# set samples 1000
# set key off
f(x)=x**4-29*x**2+100
g(x)=x**2+32*x+260
h(x)=-4+sqrt(x+16)
plot f(x) ls 2
# plot f(x) ls 2,g(x) ls 2, h(x) ls 3