%function accepts 1 double and 1 double matrix (#of_variables, [row1;row2])
%each row1 contains #of_variables+1 elements
%returns solution vector
%bsp.:
% 6x+12y=30
% 3x+ 3y= 9
% [a1,a2]=a21(2,[6,12,30;3,3,9])
% a1 = 1
% a2 = 2