help for least squares

[andrea console]

I have to solve, in least squares sense, a system of equations like:

b_1 = [a_1, 1]*[x;y];

b_2 = [a_2, 1]*[x;y];

b_3 = [a_3, 1]*[x;y];

b_4 = [a_4, 1]*[x;y];

...

b_n = [a_n, 1]*[x;y];

where b_i and a_i are sperimental values, thus affected by various sources of error.

I know that 0<x<1 and nothing about y (apart that it should be quite small).

How I can find the best solution that meets this conditions?

thanks