Solving Equations With Algebra Tiles

Grade 9s were working on solving equations today, and we started off with algebra tiles as a way to represent our equation. We started solving 2x+3=9. We know that equations are showing two expressions that are equal and balanced. We know both sides are equivalent.

When we are trying to figure out the value of x, our goal is to have x on one side of the equation, and the value of x on the other side. Starting out though, we have 2x+3. We want to just have x terms on one side, so we want to get rid of the +3. To do this we use the concept of zero pairs. We can place -3 on both sides of the equation and it will remain balanced and equal.

It will also help us simplify the equation. We know that +3 and -3 make 0, so the left side is now just 2x, and we know the right side simplifies to +6.

Now we arrange our 2x horizontally, and we split the +6 into 2 groups. We can see that each x corresponds to 3, so we know that x=3 is our answer.