function P2_10A
clear, clc, format short g, format compact
xguess = 49.5 ; 
disp('Variable values at the initial estimate');
disp([' Unknown value ' num2str(xguess) '   Function Value ' num2str(NLEfun(xguess))]); 
xsolv=fzero(@NLEfun,xguess); 
disp(' Variable values at the solution');
disp([' Unknown value ' num2str(xsolv) '   Function Value ' num2str(NLEfun(xsolv))]); 
%- - - - - - - - - - - - - - - - - - - - - -
function fTbp = NLEfun(Tbp); 
xA = .1; 
PA = 10 ^ (6.85221 - (1064.63 / (Tbp + 232))); 
PB = 10 ^ (6.87776 - (1171.53 / (224.366 + Tbp))); 
xB = 1 - xA; 
yA = xA * PA / 760; 
yB = xB * PB / 760; 
fTbp = xA * PA + xB * PB - 760;