How many times do you need to divide by ten to get from 21.7 to 2.17

You paint a 1/2 of a wall in 1/4 hour. how long will it take you to paint one wall

To describe a sequence of transformations that maps triangle abc onto triangle a"b"c", a student starts with a reflection over the x-axis.how should the student complete the sequence of transformations to map triangle abc onto triangle a"b"c"? plz

Iwant to know what 3g+5h+4g-2h is my teacher is too selfish to tell us