Which equation does this story match: The temperature is -7. Since midnight the temperature tripled and then rose 5 degrees. What was the temperature at midnight? 5x - 7=3

7=3(5+ x)

3x + 5 = -7

13 (x+ 7) = 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