Googling for "Africa longitude" returns the grossly misleading "Africa/Coordinates 8.7832° S, 34.5085° E". When you dig into why this so, it seems to be optimized for e-commerce, and no regard for accuracy.
a) This isn't the geographical centre of Africa (Lobeke National Park, 2°37'N 16°06'E, borders of Cameroon/DRC/CAR), or anywhere remotely near it. It's a random rural location 2400km ESE away, in southern Tanzania.
b) Bizarrely, that mystery location is (mis?)labeled "оф. 3, 27 ул. Хабаровская, Bila Tserkva, Russia", which label is in fact turn another place: 49.7968° N, 30.1311° E, which is actually in Ukraine not Russia, but that's another story. I wondered if this was black-hat SEO, but it also seems to be bad QA.
c) The A-plus answer for "Africa longitude" would have been ["17°31′13″W - 51°27′52″E"](https://en.wikipedia.org/wiki/Geography_of_Africa). But "17.5W - 51.5E"would have been a fine result.
d) ... and the result for "range of longitudes of Africa" is the incomplete and inaccurate non-sentence "Africa's latitude and longitude lies between 9.1021° N, 18.2812° E."(!) which Google extracted as the first sentence of the site it bizarrely chooses as its #1 hit, the small Ottawa e-commerce digital-map site https://www.mapsofworld.com/lat_long/africa.html, which is more concerned with selling stuff than accuracy (seems to have an autogenerated page with incorrect information on latitude and missing longitude for each country). Again, very questionable search relevance, no QA, and you have to wonder how on earth this was ranked above reference sources, encyclopedias, atlases, geography sites.
e) Back to the result for "Africa longitude", and less importantly, the information box with Google Flights doesn't know where it is, but cheerfully offers to sell me a plane ticket with a "15 h 35 min flight" time (from San Jose, CA), strangely precise (and wrong); but when I click through on that link it's a jumble of tickets to "Lagos, Johannesburg, Cape Town, Nairobi, Tenerife", and none with a flight-time under 18h30. And no connection to the "8.7832° S, 34.5085° E" result.
f) Searching Bing for "Africa longitude" gives lots of good map thumbnails (good job)... but their #1 site hit and text result is still the same bad site (https://www.mapsofworld.com/lat_long/africa.html) with the same wrong text "Africa's latitude and longitude lies between 9.1021° N, 18.2812° E". Don't know whether to admire MapsofWorld's SEO company, for somehow sneaking this past both search engines.
Quick comment:
I don't really blame the search engines for listing a result with bad data because sites change so often. Whose to say that the data wasn't right at one point and a recent update introduced erroneous data after it was already indexed.
It seems to me like "caveat emptor" applies here and no matter where a site falls on search rankings the reader / consumer should perform some due diligence.