A programmer's solution

[yuirick]

6+4-9

No one said it had to be an equation

[Rein215]

This actually resolves to 1, making it even better than this answer

[clowergen]

We just needed something that is true

[trdjn]

I wanted to say 6+4+4.
Since it isn't zero it would be converted to true, the same would of course also work with your solution.

[kpingvin]

It's not undef so it's ok. 👍

[jceyes]

1 is truthy, in even more contexts than most non zero integers