I need help with this question please help! Attachment posted

(6 points for answering) will give brainliest to the first correct answer!
Thanks,

Each of the four sides of a swimming pool measures 9 meters. the pool is 5 meters deep. how much water will be needed to fill it completely? a. 45 cubic meters b. 81 cubic meters c. 225 cubic meters d. 405 cubic meters reset next

If f(x)=3x+1 and f^-1=x-1/3, then f^-1(7)=

Can someone me do math because i am having a breakdown rn because i don’t get it