Answer:
(a.) Elena divided by 20 instead of negative 20
(b). y = 5/4x - 5
Explanation:
We can find Elena's mistake by putting the equation in slope-intercept forms and comparing it to Elena's process:
Once you subtract 25x from both sides, it leaves you with -20y on the right side. Thus, Elena changed -20 into 20 and divided by it instead of -20.