Error in Solving Equations

Using the "opposite operation" to "undo" and isolate the variable when solving an equation is more commonly called...

• Inverse operations

• math

• variable

• PEMDAS

What is the first step to complete when solving this equation?
10 - 3x = 4

• Subtract 10

• Add 10

• Add 3

• Divide by -3

5x - 4 + 2x = 3

• 1

• 2

• 3

• 4

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

Solve the following equation,
3x + 6 = 21

• x = 9

• x = 5

• x = 15

• x = 27

5(2x - 7) = 80

• x = 11.5

• x = 115

• x = 12

• x = 16

Solve:
-4x = 24

• 20

• -20

• 6

• -6

Solve:
7x - 3x - 8 = 24

• 8

• -8

• 3.2

• 4

Solve:
7x + 19 = -2x + 55

• 4

• 14.8

• 8.2

• -4

Solve:
2(2x + 3) = -6(x + 9)

• 2

• 6

• -6

• 7.5