Multi Step Equations

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

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

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:
5x + 6 =  66
5x - 6 = 66 -6
5x = 60
5*5x= 60*5
x = 300

• The student subtracted 6 from both sides instead of adding

• Student multiplied by 5 instead of dividing by 5

• Student got the wrong answer when subtracting 66-6

• The student did not correctly eliminate the variable from one side of the equation

Tags

CCSS.HSA.REI.A.1

Solve

• 5

• 2

• No Solution

• Infinitely Many Solutions

Tags

CCSS.8.EE.C.7A

Solve

• 2

• -8

• No Solution

• Infinitely Many Solutions

Which equation will end in "no solution"?

• 2w - 11 = 3w + 5

• 2(w + 8) = 2(2w - 19)

• w + 7 + w = 2w - 9

• 2w - 6 = 2(w - 10) + 5w

Tags

CCSS.8.EE.C.7A

Solve: 10x + 9 = 4x - 9

• 3

• 0

• -18

• -3

Solve: 2(4x-3) - 8 = 4 + 2x

• x=5/3

• x=3

• x=1

• x=2

-15 = 5a +12- 2a + 6

• -11

• -3

• 10

• 7

Tags

CCSS.8.EE.C.7B