The perimeter of a triangle can be find by adding its sides. This means to find the perimeter of the triangle shown it is necessary to add the three expressions given. Additionally, in this case, the expressions combine the letter y and regular numbers.
Due to this, the first step is to add all the "y" expressions and the numbers beside them, this means 2y + 4y + 3y = 9y, and then, the numbers remaining: +5 -2 =3. According to this, if the three sides are added to find the perimeter the final expression is 9y + 3.
