I have a successful rental business, it's regularly profitable and it's an llc

If I start another business, and that business records a loss for the year, can I write off that loss against the profits from my other business?

An example would be if I start a company that's building software and we spend 2 years building with no profits. Can I take those losses and reduce the tax burden from my rental income?

Can I write off those losses against other streams of income I have like from stocks as well?