Explanation:
What is the error?
The error was when multiplying in the brackets -2(3+x) the student mistakenly multiplied -2 • x as +2x
What should have the student have done instead?
The student would have multiplied -2(3+x) as -6-2x
Which would have made -2(3+x) = 10 to be -6-2x = 10
Work the problem correctly.
-2(3 + x) = 10
Multiply the values in the bracket by -2
- 6 - 2x = 10
Add 6 to both sides
- 6 + 6 - 2x = 10 + 6
- 2x = 16
Divide both sides by -2 to single out the variable
- 2x/-2 = 16/-2
x = -8