How to run a line function through points

[willbluet (bill bluet)]

I have 2 sets of input, one that displays 3 points and the other that displays a line function. Seperately they both work fine but I cannot figure out how to combine them so that the line function appears on the same graph as the points.

Here is the line function:

Clear[f,x];

a = -0.3;

b = 2;
f[x_] = a x + b;

Plot[f[x],{x,0,5}, PlotStyle->{{Red,Thickness[0.015]}},  AxesLabel->{"x","f[x]"}]

And here are the points:

globb1 = Graphics[{Green,PointSize[0.15], Point[{1,4}]}];

globb2 = Graphics[{Green,PointSize[0.18], Point[{3,1.4}]}];

globb3 = Graphics[{Green,PointSize[0.17], Point[{4.2, 2.3}]}];


moregreenblobs =Show[globb1,globb2,globb3,PlotRange->{{0,5},{0,5}},
     Axes->True, AxesOrigin->{0,0}, AxesLabel->{"x","y"}]

[brucem (Bruce Miller)]

Save the line plot,

plt = Plot[f[x], .... 

and combine it with the dots,

Show[moregreenblobs, plt] 

[Vitaliyk (Vitaliy Kaurov)]

Welcome to Wolfram Community, Bill! Please note how your code was formatted in special code-blocks. This makes it easy to read it and copy it. Use Spikey button in the editor - see image below. If you could also upgrade your profile information - it’d be great!

[george]

Try this:

a = -0.3;b=2;
f[x_]:=a x + b;
line=Plot[f[x],{x,0,5}, PlotStyle->{{Red,Thickness[0.015]}},  AxesLabel->{"x","f[x]"}];
points=Graphics[{Green,PointSize[0.15], Point[{1,4}],PointSize[0.18], Point[{3,1.4}],PointSize[0.17], Point[{4.2, 2.3}]}];
Show[line,points,PlotRange->{{0,5},{0,5}},
      Axes->True, AxesOrigin->{0,0}, AxesLabel->{"x","y"}]

this is what you get: