we took down a note, where the example showed us how to find the exact value of

tan (-5π / 12)

then she wrote down....

tan (-π/4) - tan (π/6)

ŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻŻ

1+tan(-π/4)tan(π/6)

and then from that, she jumped to the final answer, which is...

(-√3-1) / (-√3-1)

How did she do that?

Maybe I copied down her note wrong, cuz I keep getting a different answer...