use strict;
use warnings;

my $equation = "(2*(4*x-8)+3*x)-(10*x+1-9)"; # " = 0" omitted
$equation =~ s/x/\$_[0]/g;
my $eval = sub { eval $equation };
my $val1 = $eval->(0);
my $val2 = $eval->(1);
die "No solution for this equation\n" unless $val1 - $val2;
my $result = -$val1 / ($val2 - $val1);

printf "Result is %.10f\n", $result;