I believe question 3 is B and question 4 is B
Answer:
a
Step-by-step explanation:
Nooooooooooooooooooooooooooooooooooo
The error is that both sides of the equation have a variable. So if you were to combine your like terms, then you'd leave one side without a number and if your teacher is saying there is a left over number then it will be 0