Determine if substitution or elimination would be more convenient to use for the system below.

• A. Substitution
• B. Elimination

Answer: (A)

Verified step by step guidance

1. Step 1: Look at the given system of equations: \[\{ \begin{cases} 3x + y = -3 \\ 2y = -2x \end{cases} \]
2. Step 2: Check if either equation is already solved for one variable or can be easily solved for one variable. The second equation, \[2y = -2x\], can be simplified to \[y = -x\] by dividing both sides by 2.
3. Step 3: Since the second equation is now expressed as \[y = -x\], substitution is convenient because you can substitute \[-x\] directly for \[y\] in the first equation.
4. Step 4: Substituting \[y = -x\] into the first equation gives: \[3x + (-x) = -3\]
5. Step 5: This substitution simplifies the system to one equation with one variable, making it easier to solve. Therefore, substitution is the more convenient method for this system.