Please take a look at the following code. To change the limits on the x axis, xlim function is used.
speed = [30 45 60 75 90 120];
thinkingmin = [6 9 11 15 17 22];
brakingcarmin = [5 12 21 33 48 86];
brakingmotorcyclemin = [2 4 9 17 27 82];
plot(speed,thinkingmin,speed,brakingcarmin,'r',speed,brakingmotorcyclemin,'g')
xlim([10 160])
legend('Thinking','Braking Car','Braking Motorcycle')
figure (2)
scatter(speed,thinkingmin)
hold on
scatter(speed,brakingcarmin)
hold on
scatter(speed,brakingmotorcyclemin)
xlim([10 160])
legend('Thinking','Braking Car','Braking Motorcycle')