ClearAll;
$DefaultFont = {"Times-Roman",10};
Needs["Graphics`Graphics`"];
bods = {20.4,33.1,38.4,47.3,54.2,66.1,74.0};
elytron = {3.9,10.7,14.1,19.9,24.0,30.7,34.5};
data = Map[Thread,Transpose[{bods,elytron}]];

S[alp_,bet_] = Expand[Apply[Plus,(alp bods + bet - elytron)^2]];
H[alp_,bet_] = Expand[Apply[Plus,(alp bods^bet - elytron)^2]];

a = alp/.FindMinimum[S[alp,bet],{alp,1},{bet,1}][[2]];
b = bet/.FindMinimum[S[alp,bet],{alp,1},{bet,1}][[2]];
ah = alp/.FindMinimum[H[alp,bet],{alp,1},{bet,1}][[2]];
bh = bet/.FindMinimum[H[alp,bet],{alp,1},{bet,1}][[2]];

lp = ListPlot[data];
lin[t_] = a t + b;
hux[t_] = ah t^bh;

lin[t]
hux[t]

plot = Plot[lin[t],{t,20,74},
	AxesLabel->{"x","y"},
	PlotRange->{{0,75},Automatic},
	PlotLabel ->"y = -8.085 + 0.5829x"];
ploth = Plot[hux[t],{t,20,74},
	AxesLabel->{"x","y"},
	PlotRange->{{0,75},Automatic}];
Show[GraphicsArray[{{Show[plot,lp]}}],PlotLabel->"Figure 2.3"]