Final answer:
The length of each side of an equilateral triangle with a perimeter of 12y + 9 is 4y + 3, which is option B.Therefore, the length of each side of the triangle is 4y + 3, which corresponds to option B.
Step-by-step explanation:
The question asks us to find the length of each side of an equilateral triangle with a given perimeter.
Since an equilateral triangle has all sides of equal length, we can divide the perimeter by 3 to find the length of each side. The perimeter is given as 12y + 9.
Dividing this by 3 gives us:
(12y + 9) ÷ 3 = 4y + 3.
Therefore, the length of each side of the triangle is 4y + 3, which corresponds to option B.