To find the value of \( y \) when \( x = 3 \) using the first equation \( y = 3x - 5 \), we substitute \( x \) with \( 3 \):
\[ y = 3(3) - 5 \]
Now, calculate \( 3 \times 3 \):
\[ y = 9 - 5 \]
Finally, subtract \( 5 \) from \( 9 \):
\[ y = 4 \]
So, when \( x = 3 \), the value of \( y \) is \( 4 \).