Answer:
In which step did Sierra make a mistake? Step 2.
What should she have done instead? add the x and the 5x
Explanation:
she had the expression:
and then she multiplied the 5 by the parentheses (step 1):
no mistakes so far
then she has:
(step 2) Here is the mistake, she forgot about the 'x' that she has at the beginning of the expression.
What you should have done is add the x and the 5x, so she must a 6x in the following step (correcting the mistake):
which gives us:
