If x + y = 3 and x – y = 3, then x^2 - y^2 =
Select:
A) -4	B) 4	C) 10	D) 9	E) 40
The fastest approach has already been shown. Here's one more option.   Given:   x + y = 3   x – y = 3   Add the two equations to get: 2x = 6, which means x = 3   If x = 3, we can plug that value into either equation, to conclude that y = 0   If x = 3 and y = 0, then x² - y² = 9   Answer: 9
<result>D</result>
If x + y = 3 and x – y = 3, then x^2 - y^2 =