Graduate Management Admission Test (GMAT) Practice Test

What is the result of (x+y)(x-y)?

1. x + y

2. x² + y²

3. x² - y²

4. xy

The correct answer is: x² - y²

The expression (x+y)(x-y) represents the product of two binomials, and it can be evaluated using the difference of squares formula. This formula states that (a+b)(a-b) equals a² - b², where a and b are any two terms. In this case, we can identify a as x and b as y. Applying this formula gives: 1. First, expand the expression by multiplying: (x+y)(x-y) = x² - y². This confirms that multiplying these two binomials results in the square of the first term minus the square of the second term. Thus, the correct answer is x² - y². Understanding this formula is crucial, as it simplifies many algebra problems. In this case, since we directly applied the difference of squares, it provides a clear pathway to confirming that the answer is indeed x² - y².