Answer:
A and B
Step-by-step explanation:
a) -x+0+(-x)=0
Combine like terms.
-2x+0=0
Subtract 0 from both sides.
-2x=0
Divide both sides by -2.
x=0
b) -x-(-x)=0
Remove parentheses.
-x+x=0
0=0
Hope this helps :)
