in which of these equations would it be a good first step to add 9n to both sides?\n9n - 2 = 4n + 23\n-15 +…

in which of these equations would it be a good first step to add 9n to both sides?\n9n - 2 = 4n + 23\n-15 + 9n = 12 - 9n\n-3n + 15 = 9n - 21\ntwo of these
Answer
Explanation:
Step1: Analyze the first equation
For the equation $9n - 2=4n + 23$, adding $9n$ to both sides is not a good first - step as it will make the equation more complex. It is better to subtract $4n$ from both sides to get all $n$ terms on one side.
Step2: Analyze the second equation
For the equation $-15 + 9n=12-9n$, adding $9n$ to both sides will combine the $n$ terms on the left - hand side. The left - hand side becomes $-15 + 9n+9n=-15 + 18n$, and the right - hand side becomes $12-9n + 9n=12$. This simplifies the process of solving for $n$.
Step3: Analyze the third equation
For the equation $-3n + 15=9n-21$, adding $9n$ to both sides is not a good first - step. It is better to add $3n$ to both sides to combine the $n$ terms.
Answer:
B. $-15 + 9n = 12-9n$