why cant i update my google play services or download or update any other apps

when ever i try to download an app from play store,it crashes, so i tried dowloading the apk of google play services and when i try to install it,i get a message error parsing the package.I tried evrything like clearing data , clearing cache , removing my google account and i even tried factory data reset.Nothing worked.i still cant update play services or download any app from play store.

so please help me !!! :(
thank u in advance

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