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

equation 1: m = 6 + n
equation 2: 2m = 8 + 8n

step 1: −2(m) = −2(6 + n)
2m = 8 + 8n

step 2: −2m = −12 − 2n
2m = 8 + 8n

step 3: −12 − 2n = 8 + 8n

step 4: −20 = 10n

step 5: n = −2

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