Question

(x - y)^2 + 4z(x - y) +3z^2 (and btw ^2 means squared and this is going for 10 points)

Answer 1

(x - y)² = x² + y² - 2xy

4z(x - y) = 4zx - 4zy

3z²  =  3z²

Addum all up:

               x² + y² - 2xy + 4zx - 4zy + 3z²      

(To me, it was a lot simpler before I simplified it.)