Identify each expression that is equivalent to (7x + 3y) (7x – 3y). Tr? – 3y2
(7x)2 + (-3y)
(7x)2 – (3y)
49x2 - 9y2

I know that the last one is right, but I can’t remember what happens when the negative sign is in the parenthesis, so my brain isn’t working and I need to know between option 2&3

Graph a triangle (xyz) and reflect it over the line y=x to create triangle x’y’z’. describe the transformation using words. draw a line segment from point x to the reflecting line, and then draw a line segment from point x’ to the reflecting line. what do you notice about the two line segments you drew? do you think you would see the same characteristics if you drew the line segment connecting y with the reflecting line and then y’ with the reflecting line? how do you know?