1. The problem statement, all variables and given/known data See attached image 2. Relevant equations they are provided in the image. I see the domain is used 3. The attempt at a solution I can't figure out how they went from step one to step 2. where does the -81 come from and the 9 multiplied to the function in the middle. I tried to figure it out and all i got was divide everything by 9 then multiplying by 18 across to get 9 in the middle but that wont get me 81 on the eft hand side. Thank you in advance!