Do 5.4 plus 5.8 then do 3.4w minus 1.8w and whatever you get for each is your key to the expression. So if you were to solve the answers like A you would do 7(1.6+w) and see what you would get. Obviously A isn't the answer. Sorry, this is hard to explain. But the answer is C
if the notebooks cost 3.59 and pens cost 1.49, with x representing the notebooks and y representing the number of pens and an amount of $13, the inequality would be written as 3.59x+1.49y13