I need help answering these two questions

What is the solution of log2  (3x  -  7)  =  3? 4 5

Aproduction manager test 10 toothbrushes and finds that their mean lifetime is 450 hours. she then design sales package of this type of toothbrush. it states that the customers can expect the toothbrush to last approximately 460 hours. this is an example of what phase of inferential statistics

Math question.. plz me .. best answer all