Chapter 1, Equations and Inequalities - 1.2 Evaluate and Simplify Algebraic Expressions - 1.2 Exercises - Skill Practice - Page 15: 56

We observe that the two expressions are only equal when x or y are equal to zero. However, the expressions are not equivalent as the expressions are not always the same.

We find: $$ (x+y)^2 = x^2 + y^2 \\ x^2 +2xy + y^2 = x^2 + y^2 \\ 2xy = 0 $$ Thus, we observe that the two expressions are only equal when x or y are equal to zero. However, the expressions are not equivalent as the expressions are not always the same.