Answer:
d. X^2 - 49
Step-by-step explanation:
I will assume that the question marks are minus signs.
Let's remember what does "difference of two squares" means:
The difference of two squares is a number multiplied by itself subtracted from another number multiplied by itself (the number multiplied by itself is called squared number).
In our options, the first number is always a squared number because it's X^2 = X * X.
We just have to analyze the second number.
First, let's notice that a. and c. can't be correct because we have a sum instead of a subtract.
We have left 14 and 49 to analyze:
14 = 7*2 (it's not a squared number)
49 = 7*7 (it's a squared number)
The answer is X*X - 7*7 = X^2 - 49
