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

Equation A: y = 4 − 2z
Equation B: 4y = 2 − 4z




Step 1:
−4(y) = −4(4 − 2z) [Equation A is multiplied by −4.]
4y = 2 − 4z [Equation B]


Step 2:
−4y = 4 − 2z [Equation A in Step 1 is simplified.]
4y = 2 − 4z [Equation B]


Step 3:
0 = 6 − 6z [Equations in Step 2 are added.]


Step 4:
6z = 6


Step 5:
z = 1


In which step did the student first make an error?

Step 1

Step 3

Step 4

Step 2