Describe a line that indicates moving backward on a graph

Anybody wanna ? (picture included? )

Which of the choices below is one of the primary gases found in the atmosphere? a. helium b. carbon dioxide c. nitrogen d. argon

A2.0 μf capacitor and a 4.0 μf capacitor are connected in series across a 0.827-kv potential. the charged capacitors are then disconnected from the source and connected to each other with terminals of like sign together. find the voltage across each capacitor.