Identify which parent function is linear

Geometry. i need step by step explanation on how to do each problem.

Using the graph below, select all statements that are true. a. f(0.6)=0 b. f(-3.2)=-3 c. f(5.1)=5 d. this is the graph of the greatest integer function. e. this graph is one-to-one.

1. what is the phythaforean theorem? 2.what do we use it for? 1.what is the distance formula ? 2.what do we use it for?