Check these questions very carefully. you very much.

I can only see  #1,  #2, and  #3  in the picture.
I must say that I'm astonished.

Not only are all three of your answers correct,
but your work is neat, organized, and correct too.

You've attacked each problem in exactly the right way, the results
show it, and it's clear that you know what you're doing.

You rock !

B. because the 7 represents "seven times", x represents "a number", 12 represents "plus twelve", and -4 represents "minus four"