splitting String into String[], String->int, decimal places

/*
 * 6131: 
 * Splitting String into String[] 
 * => StringName.split("anythingHere");
 * How to turn String into int (through Integer)
 * => Integer.valueOf for Integer / Integer.parseInt for int
 * How to NOT use (int)
 * => it's only for ASCII, it doesn't change String into int
 * How to print decimal places 
 * => printf = ("%.2f", ~~)
 */

import java.util.Scanner;
public class Main
{
	public static void main(String[] args)
	{
		Scanner in = new Scanner(System.in);
		String input = in.nextLine(); 
		/*
		int a = (int)(input.charAt(0));
		int b = (int)(input.charAt(3));
		int c = (int)(input.charAt(5));
		= cannot use (int) because that's for ASCII code ㅠㅠ
		*/
		String method = input.substring(2, 3);
		
		String[] findA = input.split("x");
		String[] findBC = findA[1].split("=");
		// splits input/findA by the "character" (deletes the character)
		// and saves into String[] at index 0 and 1
		// ex. inputting 5x+4=8 as String input:
		// findA = 5
		// findBandC = +4, 8
		
		int a = Integer.valueOf(findA[0]);
		int b = Integer.parseInt(findBC[0]);
		int c = Integer.valueOf(findBC[1]);
		
		/*
		Integer.valueOf("String") (o) = used for Integer
		Integer.parseInt("String") (o) = used for int
		= 2 ways to get STRING into INT
		= saves signs (+ and -) as well!
		*/
		
		System.out.printf("%.2f",(float)(c-b)/a);
		// printf("%.3f", ~~) = 3 decimal places, etc.
	}
}