In a square tile model, one x² tile, two xy rectangular tiles, and one y² tile together represent which identity?

Correct answer: (x + y)² = x² + 2xy + y²

The correct answer is A: (x + y)² = x² + 2xy + y². Add the tile areas: one x² tile contributes x², two xy tiles contribute xy + xy = 2xy, and one y² tile contributes y². Together the pieces form a square whose side is x + y, so the total area is (x + y)². Option B has a negative middle term, which would require negative or subtractive xy tiles. Options C and D are equivalent statements of the difference-of-squares identity and involve subtraction, not two positive xy rectangles. The visual sign matters: two positive mixed tiles mean +2xy. A quick memory cue is “plus side, plus middle”; for a square of x + y, every displayed tile area is positive.