Algebra tiles in grade 9

Grade 9s are working on simplifying algebraic expressions, and adding and subtracting expressions. We are using algebra tiles to help us visualize the abstract algebra concepts.

We can represent the addition of these polynomials using tiles. Red tiles are positive, blue are negative. Big squares are x squared, rectangle tiles are x, and small square tiles are 1

When we add these together some tiles will cancel out. We end up with a trinomial -x^2+5x-2