Answer:
2 + r = 7
Explanation:
To write an equation for the image, simply look on both sides and add everything together. On the left side we have seven 1's, which adds up to 7. On the right side, we have 2 1's, which add up to 2, and a variable r. Now, we do not know the value of the variable r, so we simply leave it be. Therefore, the right side is equal to 2 + r. Since the image represents a balanced equation, the left side must equal the right side.
Left side = 7
Right side = 2 + r
Left side = Right side
7 = 2 + r
2 + r = 7