Question

What is the value of n in the equation 3n + 2(n + 2) = 9n + 12?

−4
−2
2
4

The work of a student trying to solve the equation 3(4x − 2) = 9 + 2x + 5 is shown below:

Step 1: 3(4x − 2) = 9 + 2x + 5
Step 2: 12x − 2 = 14 + 2x
Step 3: 12x − 2x = 14 + 2
Step 4: 10x = 16
Step 5: x = 1.6

In which step did the student first make an error and what is the correct step?

Step 2: 12x − 2 = 4 + 2x
Step 2: 12x − 6 = 14 + 2x
Step 3: 12x + 2x = 14 + 2
Step 3: 12x − 2x = 14 − 2

Answer 1

1. -2 I hope that helps a little bit

Answer 2

Answer with Step-by-step explanation:

3n + 2(n + 2) = 9n + 12

⇒ 3n+2n+4=9n+12

⇒ 5n+4=9n+12

⇒ 9n-5n=4-12

⇒ 4n= -8

Dividing both sides by 4

⇒ n= -2

Hence, value of n in the equation 3n + 2(n + 2) = 9n + 12 is:

-2

We have to solve the equation: 3(4x − 2) = 9 + 2x + 5

Step 1: 3(4x − 2) = 9 + 2x + 5

Step 2: 12x − 6 = 14 + 2x

Step 3: 12x − 2x = 14 +6

Step 4: 10x = 20

Step 5: x = 2

Hence, we observe that there was a mistake in Step 2

and Correct step is:

Step 2: 12x − 6 = 14 + 2x