Title: Math 7 Solve using Distributive
Course: quiz duplicate error

Show the steps you use to solve:

6(m - 2) = 12
Feedback: 6(m - 2) = 12 6m -12 = 12 6m = 24 m = 4

Show the steps you use to solve:

-3(x + 1) - 6 = 21
Feedback: -3(x +1) -6 = 21 -3x -3 -6 = 21 -3x -9 = 21 -3x = 30 x = -10

Show the steps you use to solve:

21 = -2(x + 1) - x + 5
Feedback: 21 = -2(x +1) -x +5 21 = -2x -2 -x +5 21 = -3x -2 +5 21 = -3x +3 18 = -3x -6 = x

Q: Solve:

2(n - 5) = -4
- n = 3
- n = -7 (You should add 10 to both sides after simplifying the left side.)
- n = 1/2 (Make sure you distribute the multiply by 2 to both the n and the -5)
- n = 12 (You get rid of multiplying by 2 by dividing by 2.)
A: n = 3

Q: Solve. Check your solution.

-12 = 3(4x - 5)
- x = 4 (Check your division!)
- x = \[\frac{1}{4}\]
- x = \[-\frac{1}{4}\] (Did you lose a negative?)
- x = \[-\frac{7}{12}\] (Make sure you distribute the multiply by 3 to both the 4c and the -5)
A: x = \[\frac{1}{4}\]

Q: Solve. Check your solution.

-3(g - 3) = 6
- g = -1 (Check your negative signs.)
- g = -3 (Make sure you distribute the multiply by -3 to both the g and the -3.)
- g = 1 (Well handled!)
- g = -15 (You need to subtract the 9 from both sides after you simplify the left side.)
A: g = 1

Q: Solve:

5(2c + 7) - 5 = 80
- c = 5
- c = \[\frac{9}{2}\] (Don't forget the subtract 5 part)
- c = 7.8 (Make sure you distribute the multiply by 5 to the 2c and the 7.)
- c = 11 (You should subtract the 30 from both sides once you have simplified the left side.)
A: c = 5

Error Checking: Tell what the student did wrong in solving this equation. Then give the correct solution.

3(2x - 4) = 8

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Feedback: The student forgot to multiply the 3 times the 4. x= 10/3 or x = 3.3333...

Error Checking: Tell what the student did wrong in solving the equation. Then give the correct solution.

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Feedback: The 4 should be a positive 4: -2x + 4 = 14 x =-5

Error Checking: Tell what the student did wrong in solving the equation. Then give the correct solution.

3(2x + 1) + 4 = 10

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Feedback: You can't add 6x and 3. x = 1/2 = 0.5