Answer
x=-1
Work Step by Step
When you model the equation using algebra tiles, you get 4 green tiles, 4 yellow tiles, the black bar, 1 yellow tile, and 1 green tile.
The green tile represents $x$. To isolate $x$ or the green tile by itself on one side of the equation or the black bar, subtract the 4 yellow tiles from the 1 yellow tile the other side. Subtract the 1 green tile on the other side of the black line from the green tiles on the other side, which leaves you with $3x=-3$. Three green tiles and $3$ red tiles. Divide -3 by 3. x is equal to -1.