laravel update multiple request arrays

I'm really struggling with this update method, any help will be heartfully appreciated.

I'm send multiple car number plates, that is assocaited with the resident, i can successfully store and retrive it, now i want to update it.

when I return or dd on $request->cars, it gives me this array.

array:2 [
0 => array:5 [
"id" => 10
"user_id" => 33
"car_number_plate" => "12f3456"
"created_at" => null
"updated_at" => null
]

1 => array:5 [
"id" => 11
"user_id" => 33
"car_number_plate" => "abc -123"
"created_at" => null
"updated_at" => null
]   
]

Here I find the accociated id, that needs to be updated

$userId = ResidentCar::where('user_id', $resident->id)->pluck('id')
->toArray();

it return this array.

array:2 [
0 => 10
1 => 11
]

Here i loop through the array and trying to update it.

$input = $request-cars;

foreach ($input as $row)
{
$cars[] = [
    'user_id' => $resident->id,
    'car_number_plate' => $row['car_number_plate'],
];
}

ResidentCar::whereIn('id', $userId)->update(array($cars));

it gives this error of, Array to string conversion.

and if do it with

ResidentCar::whereIn('id', $userId)->update($cars);

it gives this error.

Column not found: 1054 Unknown column '0' in 'field list' (SQL: update `resident_cars` set `0` = 33, 

Can anyone here please help on how to solve it, or any better approach thin this.

via Chebli Mohamed