Reading 45 page 58 CFAI

This is with reference to above cited material. Specifically, somehow equation 45.10 doesnt make sense to me. Please suggests.

For convenience 45.10 in CFAI TEXT states Beta (asset) = Beta (equity) [1+(1-t)debt to equity]

Check the Errata, there is an error in this equation. I strongly suggest checking the errata for each entry and annotate the books.

is it necessary to know this for the exam? i passed the L1 but dont recollect reading this one. is it there on the LOS to know this?

I failed with borderline score, now so scared to loose any marks, trying to give max.