Hey i'm Nate
So for this you want to use order of operations AKA (PEMDAS)
P: Parenthesis
E: Exponents
M: Multiplication
D: Division
A: Addition
S: Subtraction
You want to work in that order however Multiplication and Division can be alternated likewise with Addition and Subtraction. So for this question you would take the problem which is 4__ 6 -2 x4 +511 = 527 and then you plug in the signs to see which one works. The answer would be X because you would take -2x4 which is -8 then you would take 6x4 which is 24 then you subtract -8 and 24 and you get 16 then you take 16 and add 511 and then you get 527.
Therefore the answer is X