If x + y = 6 and x – y = 3, then x^2 - y^2 =
Select the correct option:
A) -4	B) 4	C) 10	D) 19	E) 40
The fastest approach has already been shown. Here's one more option.   Given:   x + y = 6   x – y = 3   Add the two equations to get: 2x = 9, which means x = 4.5   If x = 4.5, we can plug that value into either equation, to conclude that y = 1.5   If x = 4.5 and y = 1.5, then x² - y² = 4.5² - 1.5² = 19   Answer: 19
<result>D</result>
If x + y = 6 and x – y = 3, then x^2 - y^2 =