To create an equivalent equation to \( 2x + 3y = 5 \) by multiplying the entire equation by 4, you would perform the following calculation:
\[ 4(2x + 3y) = 4(5) \]
Distributing the 4, we get:
\[ 8x + 12y = 20 \]
Thus, the equation equivalent to \( 2x + 3y = 5 \) by multiplying by 4 is
\[ 8x + 12y = 20. \]