Answer:
D
Step-by-step explanation:

keep in mind that, a negative coefficient to "x", will make the graph reflect over the y-axis.
6 - (-6)
This is because two negatives make a positive, so you’ll be adding 6+6 which equals to 12 not 0
Sam=3syd+6 and sam=36, since sam=sam we can say:
3syd+6=36
3syd=30
syd=10
So Sydney has 10 pieces of candy.