To go from the equation \( 2x + 7y = 14 \) to the equivalent equation \( 4x + 14y = 28 \), you need to multiply the entire equation by 2.
So, you would multiply \( 2x + 7y = 14 \) by 2:
\[ 2(2x + 7y) = 2(14) \]
This results in:
\[ 4x + 14y = 28 \]
Therefore, the equation \( 2x + 7y = 14 \) should be multiplied by \( 2 \).