Que faire si l'installation du compositeur échoue

[root@localhost MarketingCenter]# composer install
Loading composer repositories with package information
Installing dependencies (including require-dev) from lock file
Your requirements could not be resolved to an installable set of packages.
 
  Problem 1
    - Installation request for php-amqplib/php-amqplib v2.7.0 -> satisfiable by php-amqplib/php-amqplib[v2.7.0].
    - php-amqplib/php-amqplib v2.7.0 requires ext-bcmath * -> the requested PHP extension bcmath is missing from 
    your system.
  Problem 2
    - php-amqplib/php-amqplib v2.7.0 requires ext-bcmath * -> the requested PHP extension bcmath is missing from 
    your system.
    - php-amqplib/thumper v0.5.0 requires php-amqplib/php-amqplib ^2.6 -> satisfiable by php-amqplib/php-amqplib
    [v2.7.0].
    - Installation request for php-amqplib/thumper v0.5.0 -> satisfiable by php-amqplib/thumper[v0.5.0].
 
  To enable extensions, verify that they are enabled in your .ini files:
    - /etc/php.ini
    - /etc/php.d/curl.ini
    - /etc/php.d/fileinfo.ini
    - /etc/php.d/json.ini
    - /etc/php.d/phar.ini
    - /etc/php.d/zip.ini
  You can also run `php --ini` inside terminal to see which files are used by PHP in CLI mode.

cd /usr/local/php/lib

yum install php-bcmath

yum install php-mbstring