Having issue while updating the records in laravel it is showing page not found

I have three table accidents, vehicle and people. I am performing curd operation but I am not able to update as there are multiple rows and columns. Can you please check the routes and actually idk the correct way of updating

public function edit($id)
{
        $resultset =  DB::select('select * from accidents where id = ?',[$id]);

            $vehicle =  DB::table('vehicle')
                        ->select(['vehicle.type', 'vehicle.details', 'vehicle.vehicleno', 'people.age', 'people.gender', 'people.status'])
                        ->join('people','people.vehicle_id','=','vehicle.id')
                        ->where('people.accidents_id','=',$id)
                        ->get();
            return view('updaterecord', array('accident'=>$resultset,'vehicle'=>$vehicle));
}

public function update($id)
{
    $branch = $request->input('branch');
    $roadname = $request->input('roadname');
    $caseregister = $request->input('casereg');
    $description = $request->input('description');
    $ipc_mvact =$request->input('ipc_mvact');

    $type = $request->input('vehicletype');
    $vehicleno = $request->input('vehicleno');
    $vehicledetails = $request->input('vdetails');

    $age=$request->input('age');
    $gender=$request->input('gender');
    $status=$request->input('status');

    DB::update('update acidents set branch = ?, roadname=? ,casereg=?, description=?, IPC_MVAct_Sections=?  where id = ?',[$branch,$roadname,$caseregister,$description, $ipc_mvact,$id]);

    DB::update('update vehicle set type = ?, vehicleno=? ,vehicledetails=?  where accidents_id = ?',[$type,$vehicleno,$vehicledetails,$id]);

    DB::update('update people set age = ?, gender=? ,status=?  where accidents_id = ?',[$age,$gender,$status,$id]);

    return redirect('/admin/tables');

}

// Routes

Route::namespace('Auth')->group(function () {
Route::get('/login', '\App\Http\Controllers\AdminController@index');
Route::post('/admin', '\App\Http\Controllers\AdminController@checklogin');
Route::get('/admin/dashboard', '\App\Http\Controllers\AdminController@successlogin');
Route::get('/admin/tables', '\App\Http\Controllers\AdminController@showtable');
Route::get('/admin/tables/viewrecord/{id}', '\App\Http\Controllers\AdminController@viewaccident');
Route::get('/admin/tables/editrecord/{id}', '\App\Http\Controllers\AdminController@edit');
Route::post('/admin/tables/edit/{id}', '\App\Http\Controllers\AdminController@update');});

//form

<form action="/edit/<?php echo $accident[0]->id; ?>" method="POST">