Question

Ernesto tried to determine the solution for the system of equations using substitution. His work is shown below.

x – y = 7

3x – 2y = 8

Step 1: x = y + 7
Step 2: 3(y + 7) – 2y = 8
Step 3: 3y + 7 – 2y = 8
Step 4: y + 7 = 8
Step 5: y = 1
In which step did Ernesto make the first error?

Answer 1

Step 3

Explanation:

Ernesto was doing well until he got to Step 3.

Its a little mistake but that chabges up the entire problem.

Let me explain-

In Step 2: 3(y+7)-2y is showing that you must distribute the 3 to the y and the 7 however Ernesto only did that for the y.

That would be the answer, hopw this helps.