These are examples of how you use algebra tiles to represent an equation. The large squares represent X squared, and had two sides, blue and red, to determine whether it is positive or negative (blue = positive, red = negative). There is also the long rectangles that represent X, with the positive side being green and the negative red. The side length of X is the same side length of X squared, which makes sense because X multiplied by X equals X squared. The smallest square pieces represent the number 1. The colours are yellow for positive and red for negative. These are the basic pieces used in algebra tiles, and the ones that I used today.
In the image above, you see that there are two X tiles and one 1 tile across the top. They are all positive. Down the left side, there is one positive X tile, and two negative 1 tiles. Inside the grid, you see a series of shapes that fill the area. This equals the answer to the original equation. All of the tiles correspond to the side lengths of the shapes outside of the grid. Inside there are two positive X squared tiles, four negative
In this image, the tiles that fill the space are two negative X squared tiles, five positive X tiles, and two negative 1 tiles. To find the tiles that make up this answer, you use the side length of the inner tiles and translate it to the outside, so the X squared tiles would have a side length of an X tile. An X tile would have the side lengths of an X tile and a 1 tile. To determine whether it is either positive or negative, you would just use the rules that two negatives or two positives multiplied together equal positive, and a positive multiplied by a negative equals a negative.