How to Solve Equations with java?

Question

I have three equations like the following ones:

• x + y + z = 100;
• x + y - z = 50;
• x - y - z = 10;

How can I find the values of

Answer 1

There are many ways to solve linear system equations. There is a simplest way to perform this. In the example the java code solve for two variables USING Matrix method but you can modify to perform 3 variables calculations.

import java.util.Scanner; //OBJETO SCANNER

public class SYS2 {

    public static void main (String args[]) {

        //VARIABLE DECLARATION SPACE
        int i=0,j = 0;
        float x,y;
         Scanner S = new Scanner (System.in);

         int EC3[][]= new int [2][3]; //ARRAY TO STORE EQUATION 2X3

         float DET1=0;
        float DET2 =0;


        float DETA=0;
         float DETB=0;

        //END VARIABLE DECLARATIONS
       System.out.println("Enter Equation System : ");

for (i=0; i< 2; i++) {
                for (j=0; j< 3; j++) 
                        EC3[i][j] = S.nextInt();
                }    

                System.out.println("SISTEMA DE ECUACION LINEAL: "); //THIS SENTENCE ONLY PRINT THE CATCHED VALUES OF EQUATION

                for (i=0; i< 2; i++) {
                        for (j=0; j< 3; j++) 

                              System.out.print(EC3[i][j] + "  ");

                            System.out.println();


                }    




           //    System.out.print("Determinante A de la Matriz: ");

             //    System.out.print((EC3[0][2] * EC3[1][1]) - (EC3[0][1]*EC3[1][2]) );

                for (i=0;i<2;i++) {
                        for (j=0; j<2;j++)
                                DET1=  ((EC3[0][2] * EC3[1][1]) -( EC3[0][1]*EC3[1][2]));
                }

                           //    System.out.print(DET1 );
                            //       System.out.println();

                                 for (i=0;i<2;i++) {
                                        for (j=0; j<2;j++)
                                         DET2=  ((EC3[0][0] * EC3[1][1]) - (EC3[0][1]*EC3[1][0]));
                }

                               // System.out.print("Determinante B de la Matriz: ");
                               //  System.out.println(DET2 ); 

    x = (DET1 / DET2);

    System.out.println();
    System.out.println("X = " + x);
    System.out.print("=======================");
    //FIN PARA VALOR DE X



    //COMIENZO DE VALOR DE Y

  //  System.out.print("Determinante A de la Matriz Y: ");

                                    for (i=0;i<2;i++) {
                                            for (j=0; j<2;j++)
                                         DETA=  EC3[0][0] * EC3[1][2] - EC3[0][2]*EC3[1][0];


                                        //    System.out.print(DETA );
                                          //  System.out.println();
                }


                                     for (i=0;i<2;i++) {
                                            for (j=0; j<2;j++)
                                         DETB=  EC3[0][0] * EC3[1][1] - EC3[0][1]*EC3[1][0];

                }

                                   // System.out.print("Determinante B de la Matriz Y: ");
                                   //  System.out.println(DETB );                  
                                    y = DETA / DETB;

                                    System.out.print("=======================");
                                    System.out.println();

                                    System.out.println("Y = " + y);
                                    System.out.print("=======================");
    }
}