Help idk how to do these and its hard

What signals you that factoring by grouping is the best method to use when factoring a problem?

Suppose that a households monthly water bill (in dollars) is a linear function of the amount of water the household uses (in hundreds of cubic feet, hcf). when graphed, the function gives a line with slope of 1.65. if the monthly cost for 13 hcf is $46.10 what is the monthly cost for 19 hcf?

When steve woke up. his temperature was 102 degrees f. two hours later it was 3 degrees lower. what was his temperature then?