Hi, Nanu. Your question is very vague. You don't state what kind of equation and what you want to get in return. But I'll take a swing at it:

If I wanted to find the solutions to a single-variable quadratic equation, I would enter it like this:

-32 = x^2 + 27

Wolfram|Alpha will give you some feedback about this equation including its two complex roots and its simplified form.

But here's a better bit of advise: If you ask Wolfram|Alpha a question like "How do it enter an equation?", it will often give you lots of examples of how to do it. Let's say you wanted something more specific, like systems of equations. Type "systems of equations" and Wolfram|Alpha will show you how to enter and solve them.

It takes a little getting used to asking a computer loose general questions. In the past, computers were not good at answering those types of questions. Lately they have improved a lot.

I hope this helps.