Oh, dude, it's like asking if a grilled cheese is better than a peanut butter and jelly sandwich. They both do the same thing - math stuff. The Ti-84 is like the classic choice, you know, like your go-to pair of sweatpants. The Ti-85 is like the hipster version, a bit fancier but does the same job. So, pick whichever one matches your vibe, man.
Since TI-85 was discontinued, it don't have a price, you can only buy it at websites like eBay or Amazon. But not worth it, you can buy a pretty good calculator at this moment like TI-Nspire for 150€ or 150$ (depends on where you live). But if it is too expensive you can buy TI-84 Plus or TI-84 SilverEdition which also are good and you stay well served.
That doesn't factor neatly. Applying the quadratic formula, we find two imaginary solutions: (-3 plus or minus i times the square root of 26) divided by 5.x = -0.6 + 1.0198039027185568ix = -0.6 - 1.0198039027185568iwhere i is the square root of negative one.