Equations: Error Analysis and Special Solutions

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

How many solutions does the equation below have?

5 + 2(n + 1) = 2n

• Infinite Solutions

• One Solution

• No Solution

• Two Solutions

How many solutions does the equation below have?

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

• Infinite Solutions

• No solution

• Three Solutions

• One Solution

How many solutions does the equation below have?

6(3a +1) - 30 = 3(2a - 4)

• Infinite Solutions

• No Solution

• Three Solutions

• One Solution

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

• Yes
• No

Tags

CCSS.HSA.REI.A.1

CCSS.HSA.REI.B.3

Solve
6.78x - 5.2 = 4.33x + 2.15

• 0.66
• -0.27
• -1.24
• 3

What is the error?

• Adding 2x to 3x

• Subtracting 5 from both sides

• Adding 2x to -2x

• Dividing by 5 on both sides

Tags

CCSS.HSA.REI.A.1

CCSS.HSA.REI.B.3

What is the error?

• Adding 5x to each side instead of 5

• Subtracting 7 from both sides

• Dividing -4 by 2 equals 2

• Dividing both sides by 2

Tags

CCSS.HSA.REI.A.1

CCSS.HSA.REI.B.3

What is the error?

• Subtracting 1 from both sides

• Dividing by 6 on both sides

• 3(2x+1) equals 6x +1

• x equals 3/4

Tags

CCSS.HSA.REI.A.1

CCSS.HSA.REI.B.3

What is the error?

• Adding 1 to both sides

• Distributing the negative sign when multiplying –3(x + 2)

• Subtracting 6 from both sides

• x should equal 5/3