Persamaan tiga variabel versi MATRIX

#include<coba.h>
#include <iostream>
using namespace std;
coba::coba(QDialog*parent):QDialog(parent)
{
ui.setupUi(this);
QObject::connect (ui.ok,SIGNAL(clicked()),this,SLOT(tambah()));
}
coba::~coba()
{
}
void coba::tambah()
{
cout<<"coba succes"<<endl;
QString stra = ui.a->text ();
QString strb = ui.b->text ();
QString strc = ui.c->text ();
QString strx = ui.x->text ();
QString strd = ui.d->text ();
QString stre = ui.e->text ();
QString strf = ui.f->text ();
QString stry = ui.y->text ();
QString strg = ui.g->text ();
QString strh = ui.h->text ();
QString stri = ui.i->text ();
QString strz = ui.z->text ();
bool ok;
int a = stra.toInt(&ok);
int b = strb.toInt(&ok);
int c = strc.toInt(&ok);
int x = strx.toInt(&ok);
int d = strd.toInt(&ok);
int e = stre.toInt(&ok);
int f = strf.toInt(&ok);
int y = stry.toInt(&ok);
int g = strg.toInt(&ok);
int h = strh.toInt(&ok);
int i = stri.toInt(&ok);
int z = strz.toInt(&ok);
int s = (a*((e*i)-(f*h)))-(b*((d*i)-(f*g)))+(c*((d*h)-(e*g)));
int j = (x*((e*i)-(f*h)))-(b*((y*i)-(f*z)))+(c*((y*h)-(e*z)));
int o = (a*((y*i)-(f*z)))-(x*((d*i)-(f*g)))+(c*((d*z)-(y*g)));
int t = (a*((e*z)-(y*h)))-(b*((d*z)-(y*g)))+(x*((d*h)-(e*g)));
int r = j/s;
int u = o/s;
int v = t/s;
QString straa;
QString strbb;
QString strcc;
straa= straa.number(r);
strbb= strbb.number(u);
strcc= strcc.number(v);
ui.x1->setText(straa);
ui.x2->setText(strbb);
ui.x3->setText(strcc);
ui.S->setText("Oke Juga");
}

//ini untuk file main.cpp
#include<coba.h>
#include<QApplication>
int main (int pondok,char*kaka[])
{
QApplication madrid(pondok,kaka);
coba milan;
milan.show();
return madrid.exec();
}

//Ini untuk file coba.h

#ifndef coba_h
#define coba_h
#include <QtGui>
#include <ui_coba.h>
class coba : public QDialog
{
Q_OBJECT
public :
coba (QDialog *parent=0);
~coba();
public slots:
void tambah();
private:
Ui::Dialog ui;
};
#endif