Answer:
The answer is "
"
Explanation:

In equation (a) multiply by 2 then subtract from the equation (b):

put the value of x in equation (a):

Answer:
Rusting metal can: Chemical
Boiling water: Physical
Crushing aspirin: Physical
Exploding nitroglycerin: Chemical
Answer
Its 12 months
Explanation
According to IRS, it allows for a single tax-free rollover of a 529 account per beneficiary in a 12-month period. This 12 month rule should not be violated because it can result to a 10% penalty on the earnings. However, transfers across siblings are not considered rollovers.
Answer:
The children are experiencing natural reinforcement.
Explanation:
Sandra's children are very successful in school and that is a stated natural reinforcer.
Natural reinforces occur as a result of their behavior without involving others expressing their approval of their behavior.
Sandra is trying to foster this natural reinforcement with positive social reinforcement, "but she does not always remember".