You can write the same number of positive tiles on each side of the equation.
x = - 2
Practice makes perfect
We are given an equation and we want to solve it using algebra tiles.
- 7 + x = - 9
Let's examine what each of the algebra tiles represent.
Let's write the equation using our algebra tiles. We can write the number - 7 using seven negative 1 tiles and we can write the number - 9 using nine negative 1 algebra tiles.
To solve the equation modeled by the algebra tiles, we have to get the x-tile alone on one side of the equation. We know that a positive tile and a negative tile will cancel each other out.
The x-tile will be alone if we will remove the three negative tiles that are on the same side of the equation as the x-tile. From the Addition Property of Equality, we know that we can write the same number of positive tiles on both sides of the equation and the new equation will be equivalent. Let's do it!
Next, let's rewrite the equation a little by pairing as many negative and positive tiles together as we can on both sides.
A pair of negative and positive tiles is equal to 0. This means that we can remove each matched pair. Let's do it!
We are left with the isolated x-tile on the left-hand side of the equation and two negative tiles on the right-hand side. This means that x is equal to - 2.
