To find an equation equivalent to \( 2x + 3y = 5 \) by multiplying it by 4, you would multiply each term in the equation by 4:
\[ 4(2x) + 4(3y) = 4(5) \]
Carrying out the multiplication gives:
\[ 8x + 12y = 20 \]
Thus, the equation \( 2x + 3y = 5 \) is equivalent to:
\[ 8x + 12y = 20 \]