Getting a Variable Array into the Scope of another Method in Java

I am an eighth grader in need of some help with a small project I am doing in Java. I am trying to create an application that finds the solution of two linear equations (user enters two slopes and two y-intercepts (one for each equation)). The values that are returned from the "plotter" methods are stored into arrays. I have different methods for each of the "plotter" sections. I then need to be able to access both arrays in another method. But I get a "variable not found" error for both arrays when I try to "call" the method. The "code" below is just an outline of what I am working on (a rough one, at that). Please let me know if I need to include more. Thank You!

public class fooBar{
    public static void main(String[] args){
        fooBar.doStuff1();
        fooBar.doStuff2();

        fooBar.doMoreStuff(array1, array2);
    }

    public static void doStuff1(){
        //this method defines array1 (with long values) and assigns values to it
    }

    public static void doStuff2(){
        //this method defines array2 (with long values) and assigns values to it
    }

    public static void doMoreStuff (long[] array1, long[] array2){
        //this method needs to have access to array1 and array2
        //to do the calculations and such
    }
}