Find the Error in Two 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

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

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

• Yes

• No

Which is the mistake the student made?

• The student did not distribute properly.

• The student did not combine like terms properly.

• The student did not divide by the proper value.

Tags

8.17

Which was the mistake the student made.

• The student did not combine like terms properly on the left side.

• The student did not combine like terms properly on the right side.

• The student divided by the wrong value.

• The student has x on the wrong side of the equal sign.

Tags

8.17

Consider the problem

-4(6 - y) + 4 = -4

Identify the first step that is incorrect.

What was the mistake the student make?

• The student did not distribute properly.

• The student did not combine like terms properly.

• The student did not subtract properly.

Tags

8.17

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

Did Sarah make an error? If so, which is the best description of her error?

• She didn't distribute correctly. The second step should read 3x - 12 = 24

• She didn't distribute correctly. The second step should read -3x - 12 = 24

• She didn't distribute correctly. The second step should read -3x + 12 = 24

• She didn't make an error.

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