System of linear equations with constraints

Hi! It's possible to solve system of linear equations with constraints?

Example:

1. equation: x1*0.45 + l = 0;

2. equation: x2*0.25 + l = 0;

1. constraint (equality): x1+x2 = 1;

2. constraint (inequality): x1+x2-0.09 >= 0

Without constraints code can be:

A = [0.45 0 1;
    0 0.25 1;
    1 1 0];

b = [0;0;1];

linsolve(A,b)

But with constraints?

Answer 1

[Matt J]

http://www.mathworks.com/help/optim/ug/lsqlin.html