# Pastebin Lst9P361
fernando@MBP-de-Fernando Constraint % perl6 -I. -MConstraint -e '
my $*PRINT-ISOLATED = True;
my &form = formula -> :$x!, :$y! { $x + 2*$y == 0 }

say form :42x

'
y == ( ( 0 - 42 ) / 2 )
{x => 42, y => -21}
fernando@MBP-de-Fernando Constraint % perl6 -I. -MConstraint -e '
my $*PRINT-ISOLATED = True;
my &form = formula -> :$x!, :$y! { $x + 2*$y == 0 }

say form :42y

'
x == ( 0 - ( 2 * 42 ) )
{x => -84, y => 42}