「Problem 1 - laravel/framework v6.9.0 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your systemの解決方法

#はじめに
composerをインストールし、Laravelプロジェクトを始めたら以下のようなエラーが出たので解決方法を載せておきます

````
[vagrant@localhost]$php composer.phar create-project --prefer-dist laravel/laravel myblog
Loading composer repositories with package information
Updating dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - laravel/framework v5.7.9 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.7.8 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.7.7 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.7.6 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.7.5 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.7.4 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.7.3 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.7.2 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.7.16 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.7.15 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.7.14 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.7.13 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.7.12 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.7.11 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.7.10 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.7.1 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework v5.7.0 requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - laravel/framework 5.7.x-dev requires ext-mbstring * -> the requested PHP extension mbstring is missing from your system.
    - Installation request for laravel/framework 5.7.* -> satisfiable by laravel/framework[5.7.x-dev, v5.7.0, v5.7.1, v5.7.10, v5.7.11, v5.7.12, v5.7.13, v5.7.14, v5.7.15, v5.7.16, v5.7.2, v5.7.3, v5.7.4, v5.7.5, v5.7.6, v5.7.7, v5.7.8, v5.7.9].

  To enable extensions, verify that they are enabled in your .ini files:
    - /etc/php.ini
    - /etc/php.d/20-bz2.ini
    - /etc/php.d/20-calendar.ini
    - /etc/php.d/20-ctype.ini
    - /etc/php.d/20-curl.ini
    - /etc/php.d/20-exif.ini
    - /etc/php.d/20-fileinfo.ini
    - /etc/php.d/20-ftp.ini
    - /etc/php.d/20-gettext.ini
    - /etc/php.d/20-iconv.ini
    - /etc/php.d/20-json.ini
    - /etc/php.d/20-mysqlnd.ini
    - /etc/php.d/20-pdo.ini
    - /etc/php.d/20-phar.ini
    - /etc/php.d/20-sockets.ini
    - /etc/php.d/20-sqlite3.ini
    - /etc/php.d/20-tokenizer.ini
    - /etc/php.d/30-mysqli.ini
    - /etc/php.d/30-pdo_mysql.ini
    - /etc/php.d/30-pdo_sqlite.ini
  You can also run `php --ini` inside terminal to see which files are used by PHP in CLI mode.
````
#解決方法
php-mbstring が足らなかったので以下のコードでインストールする

````
#バージョンを確認
[vagrant@localhost]$php -v

#バージョンに沿ったものをインストール
[vagrant@localhost]$sudo yum install --enablerepo=remi-php72 php-mbstring php-openssl
````

改めてプロジェクトを開始したらエラーなく、始めることができます

###まだエラーがある方はこちらの記事を参考にしてください
[<font color="LimeGreen">Laravelのインストールでmbstringがないと怒られたら</font>](https://qiita.com/don-bu-rakko/items/9b8c8b5b06ee2469fa85)