Question

1. Identify the error

2. Explain to the student what they should have done instead.
3. Show your work
1-(x+9)=-(-x-9)

Answer 1

Below

Explanation:

1 - (x+9) = 1-x -9 = -x-8 NOT 10-x

-x-8 = x+9

-8 = 2x + 9

-17 = 2x

x = - 17/2