x1=[-0.05,0.25,0.60,0,0.25,0.20,0.15,0.05,-0.15,0.15,0.20,0.10,0.40,0.45,0.35,0.30,0.50,0.50,0.40,-0.05,-0.05,-0.10,0.20,0.10,0.50,0.60,-0.05,0,0.05,0.55];
y=[7.38,8.51,9.52,7.50,9.33,8.28,8.75,7.87,7.10,8.00,7.89,8.15,9.10,8.86,8.90,8.87,9.26,9.00,8.75,7.95,7.65,7.27,8.00,8.50,8.75,9.21,8.27,7.67,7.93,9.26];A=polyfit(x1,y,1);
a=A(1),b=A(2),x11=-0.2:0.2:0.6;y1=polyval(A,x11);
plot(x11,y1,x1,y,'r*')
hold on
x2=[5.50,6.75,7.25,5.50,7.00,6.50,6.75,5.25,5.25,6.00,6.50,6.25,7.00,6.90,6.80,6.80,7.10,7.00,6.80,6.50,6.25,6.00,6.50,7.00,6.80,6.80,6.50,5.75,5.80,6.80];
y1=[7.38,8.51,9.52,7.50,9.33,8.28,8.75,7.87,7.10,8.00,7.89,8.15,9.10,8.86,8.90,8.87,9.26,9.00,8.75,7.95,7.65,7.27,8.00,8.50,8.75,9.21,8.27,7.67,7.93,9.26];B=polyfit(x2,y,2);
c=B(3),d=B(2),x21=5:0.5:7.5;y2=polyval(B,x21);plot(x21.y2,x2,y1,'go')
x1=[-0.05,0.25,0.60,0,0.25,0.20,0.15,0.05,-0.15,0.15,0.20,0.10,0.40,0.45,0.35,0.30,0.50,0.50,0.40,-0.05,-0.05,-0.10,0.20,0.10,0.50,0.60,-0.05,0,0.05,0.55];
y=[7.38,8.51,9.52,7.50,9.33,8.28,8.75,7.87,7.10,8.00,7.89,8.15,9.10,8.86,8.90,8.87,9.26,9.00,8.75,7.95,7.65,7.27,8.00,8.50,8.75,9.21,8.27,7.67,7.93,9.26];A=polyfit(x1,y,1);
a=A(1),b=A(2),x11=-0.2:0.2:0.6;y1=polyval(A,x11);
plot(x11,y1,x1,y,'r*')
hold on
x2=[5.50,6.75,7.25,5.50,7.00,6.50,6.75,5.25,5.25,6.00,6.50,6.25,7.00,6.90,6.80,6.80,7.10,7.00,6.80,6.50,6.25,6.00,6.50,7.00,6.80,6.80,6.50,5.75,5.80,6.80];
y1=[7.38,8.51,9.52,7.50,9.33,8.28,8.75,7.87,7.10,8.00,7.89,8.15,9.10,8.86,8.90,8.87,9.26,9.00,8.75,7.95,7.65,7.27,8.00,8.50,8.75,9.21,8.27,7.67,7.93,9.26];B=polyfit(x2,y,2);
c=B(3),d=B(2),x21=5:0.5:7.5;y2=polyval(B,x21);plot(x21.y2,x2,y1,'go')