hi guys/girls

im struggling with the transposition of the log to eventually find p1. im not sure how to write in this box as a equation so ive added it as a attachment to make it easier to read. i know lp and p2 from my question but need to find the value of p1.

ive put it as far as i have got but i dont think its right. any help would be great

Lp=20〖log〗_(10 ) (p2/p1)

thanks in advance