Multi-Step Equations Error Analysis

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

Tags

CCSS.HSA.REI.A.1

How many solutions does the equation below have?

5h - 7 = 5(h - 2) + 3

• Infinitely Many

• No solution

• Three Solutions

• One Solution

Tags

CCSS.8.EE.C.7A

How many solutions does the equation below have?
5 + 2(n + 1) = 2n

• Identity
• One Solution
• No Solution
• Two Solutions

Tags

CCSS.8.EE.C.7A

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

Tags

CCSS.HSA.REI.A.1

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.

Tags

CCSS.8.EE.C.7B

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

• Identity
• No Solution
• Three Solutions
• One Solution

Tags

CCSS.8.EE.C.7A

Find the Error
What error did the student make when solving the equation:
1/5x + 6 = 3/5x + 5
1x + 6 = 3x + 5
-2x + 6 = 5
-2x = -1
x = 1/2

• The student found an incorrect common denominator
• The student did not multiply all terms by the common denominator
• The student did not use opposite operations appropriately
• The student did not correctly eliminate the variable from one side of the equation

Tags

CCSS.HSA.REI.A.1

CCSS.HSA.REI.B.3