Final answer:
The expressions 2y + 5y + 2y and 11y are equivalent and represent the sum of the angles of a triangle. The expression 9y does not combine all angles, and 2y * 5y * 2y is a product, not a sum.
Step-by-step explanation:
The question asks us to write two equivalent expressions to represent the sum of the angles of a triangle. The expressions 2y + 5y + 2y and 11y both represent the sum of the angles of a triangle. Expression (a) combines the three angle measures into a single sum, while expression (d) simplifies this sum to a single term. The expressions (b) 9y and (c) 2y * 5y * 2y are not equivalent to the others. Expression (b) is not equivalent because it does not combine all the angles, and expression (c) is a product, not a sum.