Export Plot to PDF results very messy

Question

When my nice looking DiscretePlot results are exported as PDF, they look very different from the original plots. For example, my original plot in Mathematica looks like

When this is exported as PDF, I have

Is there anyway I can export my plots exactly as they look?

EDIT

My model is a discrete dynamic model consisted of around ten variables and ten equations. So I used DiscretePlot, not Plot.

My code is:

a1 = 0.85;
a2 = 0.25;
L1 = 0.07;
L2 = 0.3;
w = 2;
b1 = 1;
b2 = 0.2;
x1[0] = 1;
x2[0] = 1;
p1[0] = 0.5;
p2[0] = 0.2;
mul0 = 0.9
mul1 = 3.9
mul2 = 2.8
H[0] = 1
r[0] = 0.1

x1[t_] := x1[t] = G*x1[t - 1];
x2[t_] := x2[t] = G*x2[t - 1];
mul[t_] := mul[t] = mul0 + mul1*r[t - 1] + mul2*(G - 1)
H[t_] := H[t] = H[t - 1]*G
m[t_] := m[t] = (mul[t]*H[t])/(L1*x1[t] + L2*x2[t])
exp[t_] := exp[t] = (m[t] - p2[t - 1]*w)/(p2[t - 1]*w)
r[t_] := r[t] = (exp[t]*(p2[t - 1]*w*L1*x1[t] + 
   p2[t - 1]*w*L2*x2[t]))/((p1[t - 1]*a1 + p2[t - 1]*w*L1)*
  x1[t] + (p1[t - 1]*a2 + p2[t - 1]*w*L2)*x2[t])
p1[t_] := p1[t] = (1 + r[t])*(p1[t - 1]*a1 + p2[t - 1]*w*L1)
p2[t_] := p2[t] = (1 + r[t])*(p1[t - 1]*a2 + p2[t - 1]*w*L2)
check[t_] := check[t] = (x1[t] - a1 x1[t] - a2 x2[t])*p1[t] +
x2[t]*p2[t] -m[t]*(L1*x1[t] + L2*x2[t])

n1 = 1;
n2 = 200

Plot3 = Show[GraphicsRow[{DiscretePlot[p1[t], {t, n1, n2}, 
 PlotLabel -> "Price 1", BaseStyle -> {FontSize -> 10}, 
 PlotRange -> {{n1, n2}, {0, 10}}, Filling -> None, 
 Joined -> True], 
DiscretePlot[v1[t], {t, n1, n2}, PlotLabel -> "Price 2", 
 BaseStyle -> {FontSize -> 10}, PlotRange -> {{n1, n2}, {0, 5}}, 
 Filling -> None, Joined -> True], 
DiscretePlot[check[t], {t, n1, n2}, PlotLabel -> "check", 
 BaseStyle -> {FontSize -> 10}, PlotRange -> {{n1, n2}, {0, 10}}, 
 Filling -> None, Joined -> True]}], ImageSize -> Full]
Export["Plot3.pdf", Plot3];

Answer 1

1. Select the cell with the plots
2. Copy-paste into a new empty notebook
3. File -> Printing Settings -> Page Setup...
4. Choose paper size A3 and landscape
5. Save as a new pdf
6. Go to https://www.cutepdf-editor.com/edit.asp
7. Upload pdf and crop it and save it

I have experienced that some of the symbols from mathematica (such as capital gamma) appear wrong when the file is loaded in cutepdf, but when I save them and open in adobe reader, they are right again.

Answer 2

How are you producing the pdf? What operating system are you using? You haven't included any code, but in my attempt I don't reproduce your problem,

GraphicsRow[{
  Plot[(20 Exp[-t/2] + 2 Exp[-t/20] Cos[t] + 3), {t, 0, 50}, 
   PlotLabel -> "Price 1"],
  Plot[(30 Exp[-t/2] - 2 Exp[-t/5] Cos[t] + 14), {t, 0, 50}, 
   PlotLabel -> "Price 2"],
  Plot[(2 Exp[-t/2] - 2 Exp[-t/25] Cos[t] + 6), {t, 0, 50}, 
   PlotLabel -> "Price is Right"]}, ImageSize -> 700]
Export["pricecheck.pdf", %]

and here is a comparison of the results