use warnings;
use strict;
use Data::Dumper;

my $equation = '979x + 87y - 8723z = 274320';
my @parts = ($equation =~ /(?:(.*?)([xyz]))/ig);
print Dumper(\@parts);

__END__

$VAR1 = [
          '979',
          'x',
          ' + 87',
          'y',
          ' - 8723',
          'z'
        ];