Welcome to the forum! I do recommend you use Liperior or CNHL as they are cheap, and they have good quality. You can fly with that specific LiPo until a cell dies, or the LiPo puffs up. Or in the case of accidental damage.
I dont recommend any of the "Amazon.com" LiPos. So far out of all the ones I've tested, theyre all junk compared to Liperior and CNHL. That being said I havent tested them specifically but I have tested a lot of them. Just my .02
Will they work? Sure, up to a point but a Liperior Pro 6S 5000mAh will work better, last longer, and is only $66 instead of $99 like the Yowoo. That is of course if they fit. Make sure the pack size will fit in the TREX550. If that specific pack doesn't fit RCBattery.com has others 6S pack options on their website and CNHL has some too that are comparable quality and price and they also might have packs that will fit.
Welcome to the RCT mad house!!! I don't suggest using those lipos for anything. Like @Greywolf74 said they are junk.. you will be better off going with the Liperior lipos. You can get them from RCBattery.com and they are better quality and priced, or the CHNL. But you will have to get the measurements of the battery compartment to make sure the lipos fit. That's what will be the biggest factory to make sure they fit...and how many time can you fly. That really can't be answered 100%.. it comes down to how well do you take care of you lipos. And the quality of them..