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

Equation A: y = 15 - 2z

Equation B: 2y = 3 - 4z

Step 1: - 2 (y) = - 2 (15 - 2z) [Equation A is multiplied by - 2.]

2y = 3 - 4z [Equation B]

Step 2: - 2y = 15 - 2z [Equation A in Step 1 is simplified.]

2y = 3 - 4z [Equation B]

Step 3: 0 = 18 - 6z [Equations in Step 2 are added.]

Step 4: 6z = 18

Step 5: z = 3

In which step did the student first make an error?

Step1

Step 2

Step 3

Step 4

Question

Mathematics

Ellis Hays

28 October, 02:22

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

Equation A: y = 15 - 2z

Equation B: 2y = 3 - 4z

Step 1: - 2 (y) = - 2 (15 - 2z) [Equation A is multiplied by - 2.]

2y = 3 - 4z [Equation B]

Step 2: - 2y = 15 - 2z [Equation A in Step 1 is simplified.]

2y = 3 - 4z [Equation B]

Step 3: 0 = 18 - 6z [Equations in Step 2 are added.]

Step 4: 6z = 18

Step 5: z = 3

In which step did the student first make an error?

Step1

Step 2

Step 3

Step 4

+1

Answers (1)

Know the Answer?

Kimberly Neal · Answer 1

Option: step 2.

Because the student divided only the right side by 2. If you divide one side by a number you have to do the same with the other side to maintain the equality.