Answer
True.
Work Step by Step
Equations are equivalent if they have equal solution sets.
$\left[\begin{array}{ll}
3y-1=11 & 3y-7=5\\
3y=12 & 3y=12\\
y=4 & y=4
\end{array}\right]$
Both equations have the solution set $\{4\}$, so, the statement is true.