Question

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

Equation A: y = 15 − 2z
Equation B: 3y = 3 − 4z


Step 1: −3(y) = −3(15 − 2z) [Equation A is multiplied by −3.]
3y = 3 − 4z [Equation B]
Step 2: −3y = 15 − 2z [Equation A in Step 1 is simplified.]
3y = 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?
Step 4
Step 3
Step 2
Step 1

Answer 1

In which step did the student first make an error?

Answer: Step 2

Step 2 should be:

−3y = -45 + 6z