Final answer:
Expansionary and contractionary fiscal policies are designed to have opposing effects on the economy, with one stimulating and the other dampening aggregate demand, respectively. Using them together would offset their individual impacts.
Step-by-step explanation:
The set of fiscal policies that would tend to offset each other are expansionary and contractionary fiscal policies. During a recession, an appropriate response would be to implement an expansionary fiscal policy, which involves increasing government spending or decreasing taxes to stimulate aggregate demand. Conversely, during an economic boom, where aggregate demand has pushed the level of output above potential GDP causing inflation, contractionary fiscal policy is recommended. This involves decreasing government spending or increasing taxes to dampen aggregate demand. If these two types of policies are used simultaneously or in quick succession, their effects would tend to cancel each other out, lessening the overall impact on the economy.