Can someone tell me the answer to 9c+3+13–4c+4–8c??

Can you also make your answer detailed? I also want to practice onthe answer I'm given

In a graph with several intervals o data how does a constant interval appear? what type of scenario produces a constant interval?

On #16 : explain how factoring a trinomial, ax^2+ bx+ c, when a does not equal 1 different from factoring a trinomial when a = 1.

Jude is making cement for a driveway. the instructions show the amount of each ingredient to make 1 batch of cement. complete each statement to adjust the ingredients for each new situation if jude uses these instructions.