Question

The work of a student to solve the equation 3(2x – 4) = 8 + 2x + 6 is shown below:

Step 1: 3(2x – 4) = 8 + 2x + 6
Step 2: 5x – 7 = 14 + 2x
Step 3: 5x – 2x = 14 + 7
Step 4: 3x = 21
Step 5: x = 7
In which step did the student first make an error and what is the correct step? (5 points)
Step 2; 6x – 12 = 14 + 2x
Step 2; 6x – 7 = 2(6 + x + 4)
Step 3; 5x – 2x = 14 – 7
Step 3; 5x + 2x = 14 + 7

Answer 1

id say step 2

Explanation:

Answer 2

If you would like to know in which step did the student first make an error and what is the correct step, you can calculate this using the following steps:

3(2x - 4) = 8 + 2x + 6
6x - 12 = 8 + 2x + 6
6x - 12 = 14 + 2x ... Step 2
6x - 2x = 14 + 12
4x = 26
x = 26/4 = 13/2

The correct result would be Step 2; 6x - 12 = 14 + 2x.