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

equation 1: m = 8 + 2n
equation 2: 3m = 4 + 4n

step 1:
−3(m) = −3(8 + 2n) [equation 1 is multiplied by −3.]
3m = 4 + 4n [equation 2]

step 2:
−3m = −24 − 6n [equation 1 in step 1 is simplified.]
3m = 4 + 4n [equation 2]

step 3:
−3m + 3m = −24 − 6n + 4n [equations in step 2 are added.]

step 4:
0 = −24 − 2n

step 5:
n = −12

in which step did the student first make an error?

step 4

step 3

step 2

step 1