%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