I don't know much about Excel, but the simplest type of thing would be to use Solve or Reduce e.g.
Solve[ 24*x==96, x]
Note some differences in syntax, especially use "==" for Equal as "=" is reserved for Set. Note that you can use natural language inputs, e.g. in Wolfram Alpha, if you find this easier.
Wolfram Language is pretty powerful in solving equations, and on the other hand there are more choices for how to solve something. Sometimes there is no answer (like a real x with x^2==-1) and you can then use minimization to get the closest possibility. Since solving equations can become arbitrarily hard I would guess that solving is better done in Wolfram Language than in Excel.
The idea of searching for a value is an important one in Wolfram's way of doing things. For example, find the smallest elementary cellular automaton that displays random behavior from a single black cell? Sounds hard. You don't need to understand what this is, just make a table of graphics and pick out the answer.
Table[ArrayPlot[CellularAutomaton[rule, {{1},0},{100,All}],PlotLabel->rule],{rule,0,255}]
(See Stephen Wolfram's A New Kind of Science )
