when i plot a function, others disappear

When i write the code below, matlab does not plot all the functions but one. you can see what i mean. Where did i make a mistake? Thank you for upcoming helps.

t = [-5:0.1:10];
x = t.^3 - 2*t + 9;
y = 6*t.^5 - t;
z = t.^2 + 7;
plot(t,x,'r:')
hold on
plot(t,y,'g--')
hold on
plot(t,z,'b-.')
hold off

Answer 1

[the cyclist]

All three lines are being plotted. The issue is that the green line goes to huge values, so you don't see the separation between the other two. Here, I've plotted over a much smaller range, so you see that:

t = [-1.5:0.01:1.5];
x = t.^3 - 2*t + 9;
y = 6*t.^5 - t;
z = t.^2 + 7;
plot(t,x,'r:')
hold on
plot(t,y,'g--')
hold on
plot(t,z,'b-.')
hold off

FYI, you don't need to repeatedly use hold on ...

t = -1.5:0.01:1.5
x = t.^3 - 2*t + 9;
y = 6*t.^5 - t;
z = t.^2 + 7;
figure
hold on
plot(t,x,'r:')
plot(t,y,'g--')
plot(t,z,'b-.')
hold off

[Omer Seker]

thank you so much for the reply and also thanks for the hold on shortcut