Question

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?

A. Step 1
B. Step 2
C. Step 3
D. Step 4

Answer 1

step 2

should be :
-2y = - 30 + 4z for equation A