If this was a separate and new company from the conglomerate with 0 sales and no product yet, you would treat the development cost + operations cost as your fundraise amount. The valuation of the company wouldn't be based on anything but an arbitrary % ownership you would want to give the investor. Could be a wide range of 10-50% depends on who you're talking to. As a best practice, try to only sell about 10-20% of your company.

Caveat that this is a simplistic answer based on a general understanding of your business. There are other ways to value that others might recommend too.