This is from a a question i posted a while back but never got a good response to.

"Consider the function f(x)=2-3x with domain R ( real numbers). Let A = [-1,3), B=(2,5]."

now another question is findf|A composite XB(big with with subscript B)

My teacher showed the graph for it. But i dont understand it.

Could someone please help in how this graphs comes to be?? Thanks.