Help me please !! I'm panicking please help

Jayda's house is located at (1, 5). she can walk in a straight line to get to cristian's house. a fast-food restaurant is located at (11, 0) and partitions the way from jayda's house to cristian's house by a ratio of 5: 1. find the coordinate of cristian's house. me . im a little stuck

Hurry if the population of of an ant hill doubles every 10 days and there are currently 100 ants living in the ant hill what will the ant population be in 20 days

What is the domain of the step function f(x)=[2x]-1?