You don't need to know many guitar scales to play guitar solos – but you do need to know this one. The minor pentatonic is good enough for players including Angus Young, Slash, Eric Clapton ...

The reason for this is because the E7 features a G# note, the Major 7th in the key of A minor. Our A minor pentatonic and A natural minor scales by contrast feature a b7th interval, or G natural.