restart:

x:=[1.1,3.2,4.1,5.8,8.9,10.9]; f:=[3.1,9.8,12.6,17.9,27.1,31.9];

NiM+SSJ4RzYiNygkIiM2ISIiJCIjS0YpJCIjVEYpJCIjZUYpJCIjKilGKSQiJDQiRik=

NiM+SSJmRzYiNygkIiNKISIiJCIjKSpGKSQiJEUiRikkIiR6IkYpJCIkciNGKSQiJD4kRik=

a:=(nops(x)*sum(x[i]*f[i],i=1..nops(x))-sum(x[i],i=1..nops(x))*sum(f[i],i=1..nops(x)))/(nops(x)*sum((x[i])^2,i=1..nops(x))-(sum(x[i],i=1..nops(x)))^2); b:=(sum((x[i])^2,i=1..nops(x))*sum(f[i],i=1..nops(x))-sum(x[i]*f[i],i=1..nops(x))*sum(x[i],i=1..nops(x)))/(nops(x)*sum((x[i])^2,i=1..nops(x))-(sum(x[i],i=1..nops(x)))^2); E:=sum((f[i]-a*x[i]-b)^2,i=1..nops(x));

NiM+SSJhRzYiJCIrM2tBZEghIio=

NiM+SSJiRzYiJCIrcE5dITQkISM1

NiM+SSJFRzYiJCIrcHpHcTUhIio=