How to declare variable in Mathematica and use them later

Question

I am very new to Mathematica and I was curious about how one can declare variable and use them later in function. I tried to do as below but I'm getting empty result in Graph

Here I've declared two variable one and two and tried to use them later but it didn't output the result.

Thanks in advance.

Answer 1

Try this

one:=3*x^2/2;
two:=x;
Show[Plot[one/two,{x,0,15}],ListPlot[{1,3,7,9,10,11,14}]]