Question

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

Equation 1: m = 8 + 2n
Equation 2: 3m = 4 + 4n

Step 1: −3(m) = −3(8 + 2n) [Equation 1 is multiplied by −3.]
3m = 4 + 4n [Equation 2]
Step 2: −3m = −24 − 6n [Equation 1 in Step 1 is simplified.]
3m = 4 + 4n [Equation 2]
Step 3: −3m + 3m = −24 − 6n + 4n [Equations in Step 2 are added.]
Step 4: 0 = −24 − 2n
Step 5: n = −12

In which step did the student first make an error?
Step 4
Step 3
Step 2
Step 1

Answer 1

@563blackghost @Shadow

Answer 2

step 2 has the two equations
−3m = −24 − 6n
3m = 4 + 4n

step 3 has the added equations

−3m + 3m = −24 − 6n + 4n

notice how the 4 from equation 2 in step 2 vanished

so one might say the error is in step 3 b/c he forgot the 4 from the second equation