Given the following rules in a “back-chaining” expert system application:

A ∧ not (B) ⇒ C (.9)

C v D ⇒ E (.75)

F⇒A (.6)

G⇒ D (.8)

The system can conclude the following facts (with confidences):

F (.9)

B (−.8)

G (.7)

Use the Stanford certainty factor algebra to determine E and its confidence.