(help ASAP) Which function has a constant additive rate of change of -1/4?

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.

Does anyone know how to do geometryme with this problem

Secant be and cf intersect at point d inside a what is the measure of cde