Question

A teacher asked her student to solve the equation 3(3x + 2) - 12 = 6x + 9 for x. The student's work is shown3(3x + 2) - 12 = 6x + 9Step 1: 9x + 6 - 12 = 6x + 9Step 2. 9x - 6 = 6x + 9Step 3. 3x - 6 = 9Step 4:3x = 15Step 5 x = 12In which step did the student make his first error? Explain the mistake

Answer 1

Analysing each step, we have:

Step 1: Correct, the distributive property was used correctly.

Step 2: Correct, subtraction of 6 and 12.

Step 3: Correct, subtracted 6x from both sides.

Step 4: Correct, added 6 to both sides.

Step 5: Incorrect, the first side was divided by 3, but the second side was subtracted by 3, instead of being divided by 3.