Explanation for Question 2 From the Math (No Calc) Section on the 2017 May Sat
Let's take a look at question number two, question number two. 2 First gives us the function and then ask where the value of F of 3 seven minus F of five. Whenever we have anything inside 4 the parentheses after the F we just read it as F of something in 5 this case, it's F of X. And in these cases, 6 we just read it with the number. So F of seven minus F of 7 five, what we do when we have F with parentheses a 8 number inside is we just replace whatever has 9 an X in the function with this number. 10 So if F of X equals X plus three, 11 over to F of seven, 12 it's just the same thing. But whenever you see an X, 13 it has a seven, so seven plus three, 14 over two, we then simplify that we got 10 over two 15 or five. Now it's the same thing with F of five F 16 of five equals five plus three, 17 over two, we simplify and we got eight over two or 18 four. Now what we want to know is F of seven 19 minus F of five. So we just substitute what we got 20 for F of seven and F of five, seven. 21 We got five minus of a five, 22 which we got for five minus four is one or B.