Question 174101
First, congratulations on keeping your mind sharp by learning new (math) skills.
First, we'll do some of the evaluations:
{{{f(x) = 5x-3}}} Substitute x = 1:
{{{f(1) = 5(1)-3}}}
{{{f(1) = 5-3}}}
{{{highlight(f(1) = 2)}}}
Substitute x = 16:
{{{f(16) = 5(16)-3}}}
{{{f(16) = 80-3}}}
{{{highlight(f(16) = 77)}}}
Repeat the above proceess, substituting, in turn, x=2, x=4, x=8. 
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{{{f(x) = x^2-3x+2}}} Substitute x = 1
{{{f(1) = 1^2-3(1)+2}}}
{{{f(1) = 1-3+2}}}
{{{highlight(f(1) = 0)}}}
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Substitute x = 16:
{{{f(16) = (16)^2-3(16)+2}}}
{{{f(16) = 256-48+2}}}
{{{highlight(f(16) = 210)}}}
Repeat the above process, substituting, in turn, x=2, x=4, x=8.
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{{{f(x) = 2x^3+7x^2-x-1}}} Substitute x = 2:
{{{f(2) = 2(2)^3+7(2)^2-2-1}}}
{{{f(2) = 2(8)+7(4)-2-1}}}
{{{f(2) = 16+28-3}}}
{{{highlight(f(2) = 41)}}}
Substitute x = 8:
{{{f(8) = 2(8)^3+7(8)^2-8-1}}}
{{{f(8) = 2(512)+7(64)-8-1}}}
{{{f(8) = 1024+448-9}}}
{{{f(8) = 1472-9}}}
{{{highlight(f(8) = 1463)}}}
Repeat the above prcess, substituting, in turn, x=1, x=4, x=16.
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To answer the second part of the question, it is probably best to graph each of the functions (Red: {{{f(x) = 5x-3}}}), (Green: {{{f(x) = x^2-3x+2}}}), (Blue: {{{f(x) = 2x^3+7x^2-x-1}}}) and examine the graphs to determine their behaviour at each of the specified values of the independent variable (x=1, x=2, x=4, x=8, x=16).
{{{graph(400,400,-5,10,-3,20,5x-3,x^2-3x+2,2x^3+7x^2-x-1)}}}