Answer:
0
Step-by-step explanation:
x = - 9 + 9
= 0
(If you owe 9 apples to your friend, and he gives you 9 apples, how much do you owe him now? 0, because you can give him back the 9 apples and you will owe him nothing else.)
(Or you can just rewrite the equation as x = + 9 - 9
= 0
because 9 minus 9 is 0.)
