Question

Which of the following shows how the number 7 can be rewritten with the difference of squares identity?

Answer 1

If we let x and y be the two numbers such that the difference of their squares will give 7, we have the equation,
                             x^2 - y^2 = (x + y)(x - y) =  7
From the given choices, the squares are 16 and 9 which are squares of 4 and 3, respectively. Therefore,
                              16 - 9 = (4 + 3)(4 - 3) = 7
Thus, the answer is letter A.