Question

The work of a student to solve a set of equations is shown:

Equation 1: m = 8 + 2n
Equation 2: 6m = 4 + 4n


Step 1: −6(m) = −6(8 + 2n) [Equation 1 is multiplied by −6.]
6m = 4 + 4n [Equation 2]
Step 2: −6m = −48 − 12n [Equation 1 in Step 1 is simplified.]
6m = 4 + 4n [Equation 2]
Step 3: −6m + 6m = −48 − 12n + 4n [Equations in Step 2 are added.]
Step 4: 0 = −48 − 8n
Step 5: n = −6


In which step did the student first make an error?
Step 3
Step 5
Step 4
Step 2

Answer 1

the Answer is step 3

Answer 2

If you would like to know in which step did the student first make an error, you can find this using the following steps:

m = 8 + 2n
6m = 4 + 4n
________________
-6(m) = -6(8+2n)
6m = 4 + 4n
________________
-6m = -48 - 12n
6m = 4 + 4n
________________
-6m + 6m = -48 - 12n + 4 + 4n ... Step 3

0 = -44 - 8n

8n = -44

n = -44/8 = -11/2

The correct result would be: Student made an error in Step 3.