What is the perpendicular line slope of -2x-9y=4

Rosy waxes 2/3 of her car with 1/4 bottle of car wax. at this rate, what fraction of the bottle of car wax will rosey use to wax her entire car

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