Diagnostic codes 25(air-fuel ratio lean malfunction) and 71(EGR system malfunction)

I bought this corolla and checked diagnostic codes. 25 and 71 are what flashed. I guess my first question is: I found that the main air cleaner intake hose was way loose on the air cleaner side. Would that being so loose (the clamp was not there and hose was almost disconnected) cause these two codes to flash.

Also can you tell me, and not quoting the things from book, bcuz I don't really understand, what steps in sequence, I can perform in order to cure these two codes?

Any and all answers are so greatly appreciated. Thank you. Respectfully, Richard Carson