They’re more than equal

They're not equal at all 🙄

If a=2, b=3...

1/ab=1/(2x3)=1/6

1/axb=1/2x3=3/2=1.5

It’s an identity, which you’d understand

Nope! axb==ab is an identity, which is NOT how it's written, "illiterate fraud" as per your other comment

if you weren’t lying about being a teacher

says person who is lying about what the textbook says 🙄