Can someone answer this quetion please answer it correctly if it’s correct I will mark you brainliest

Simply 8x squared + 5(7x squared- x) - 2x =

Sum is 17 and their difference is 3

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