3. A math student has a plan to solve the following system by the elimination method. To eliminate the \( x \) -terms, he wants to multiply the top equation by \( 7 \) . What should he multiply the second equation by so that when he adds the equations, the \( x \) -terms are eliminated?

\( - 3 x - 7 y = - 56 \)

\( - 7 x + 10 y = 1\)