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


equation a: y = 4 – 2z

equation b: 6y = 2 – 4z



step 1: –6(y) = –6(4 – 2z) [equation a is multiplied by –6.]

6y = 2 – 4z [equation b]

step 2: 6y = 4 – 2z [equation a in step 1 is simplified.]

6y = 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 4

step 3

step 2

step 1