please help

If a company buys another company they allocate the purchase price 1st to tangible assets and then to identifiable intangibles and then to goodwill. There have been a significant number of acquisitions over the past few years that created a massive amount of intangibles and goodwill on corporate balance sheets. A couple of years after acqutsition we have seen companies write off large amount of intangibles and goodwill. A couple of examples are Kraft Heinz, Baker Hughes, and ATT -- take one of them identify the write off, the amount of write-off. Provide 3 reasons they needed to perform the write down. What may that tell us about the original purchase price