x1 = [0, 10, 20, 30, 40, 50, 60];
y1 = [120, 100, 80, 60, 40, 20, 0];
plot(x1,y1)

function yy=Regress(x, y, n, al, a0, syx, r2)
sumx=0; sumxy=0;st=0;
sumy=0;sumx2=0;sr=0;
for i = 1:n
sumx = sumx + x(i);
sumy = sumy + y(i);
sumxy=sumxy+x(i)*y(i);
sumx2=sumx2+x(i)*x(i);
end
xm = sumx/n;
ym = sumy/n;
a1 = (n*sumxy - sumx*sumy)/(n*sumx2 - sumx*sumx)
a0 = ym - a1*xm
for i = 1:n
st = st + (y(i) - ym)^2;
sr = sr + (y(i) - a1*x(i) - a0)^2;
end
syx = (sr/(n - 2))^(0.5);
r2 = (st - sr)/st;
yy=a0;
yy=a1;
end

fplot(@(x) 120-2*x,[0 60],'b');
hold on
plot(x1,y1,'o')
hold off
grid on;
a00=Regress(x1, y1, 7,2,18,2,4);
fprintf("Estos son los valores de a0 y a1.\n",a00)