Math basics › Precalculus
Piecewise functions
One rule per stretch of x
Each line says which formula applies and where. Check which interval your x falls in first, then use only that rule.
The endpoints are the whole question
Watch whether each piece uses ≤ or <. At a boundary only one piece is allowed to own the point, or it is not a function.
Continuous or not
Put the boundary value into both pieces. Same answer means the graph joins up; different answers mean it jumps.