Solving Equations Error Analysis

Did they combine the variables correctly?

• Yes

  You should do the opposite

• Yes

  You should do what you see

• No

  They should have done the opposite

• No

  They should have done the what saw

Which step contains the error?

• Step 1

  Distribute

• Step 2

  Combine Like Terms

• Step 3

  Add or Subtract

• Step 4

  Multiply or Divide

Find the error

The student should have multiplied by the _.

When you multiply and distribute, _ the sign and keep the result.

Find the error in the problem below
19 - 2k = 3k - 1
     +3k   +3k
19 + 1k = -1
-19           -19
k = -20

• They should have divided by 1 for the last step

• They should add 19 instead of subtracting 19

• I can not find an error

• Instead of adding 3k they should subtract 3k

Is the solution below correct?
5d = 2d - 18
-2d   -2d
3d = -18
d = 6

• Yes

• No

Is the solution below correct?
-6z + 13 = 7z
+6z           +6z
13 = 13z
z = 1

• Yes

• No

How many solutions does the equation below have?
6(3a +1) - 30 = 3(2a - 4)

• Identity

• No Solution

• Three Solutions

• One Solution

4x - 3 = -2x + 4
6x - 3 = 4
6x = 7
x = 7/6

• There is no error

• They should have subtracted 2x

• They should have subtracted 3

• it should be 6/7

5 + 2(n + 1) = 2n
Bill says the first step is to add and get
7(n + 1) = 2n

• Bill is correct

• Bill is wrong; he should have distributed the 2 first.

• Bill is wrong; he should have subtracted 5 from both sides first.

• Bill is wrong; he should have divided by 2 firat.