Could not find build gradle 3.0.1

Any clarification on this subject would be greatly appreciated.
I know this has been answered many times but my current issue is that I don’t know where or in what file (s) to add this to:

buildscript {
    repositories {
        google()     // <-- add this 

    dependencies {
        classpath ''

And this:

allprojects {
    repositories {

Or if that even solves my issue, since I haven’t tested it yet.

My initial problem:

The issue seemed to appear after updating both gradle and Android studio.
I’m currently working on a project using libGDX to make an Android app called CastleCrush. When I try to launch a desktop application to test it, it won’t launch, and I get this error:

Error:Gradle: A problem occurred configuring root project 
    > Could not resolve all files for configuration ':classpath'.
      > Could not find
 Searched in the following locations:
 Required by:
     project :

When launching with a virtual Android device it launches just fine.
I’m not working on this project alone and collaboration is done via Git, if that makes any difference. None of the other project members seem to have this issue.