Expressions, Equations, and Relationships>Determining Equivalence of Expressions with Models and Algebraic Representations(TEKS.Math.6.7.C) Practice Test

Multiply the terms: $5y\cdot 2y=10y^2$, so it matches $7y$.

Subtract coefficients: $5y-2y=3y$, so the expressions are equivalent.

Combine like terms: $5y+2y=(5+2)y=7y$.

They are not equivalent because $y$ could be any number.