Answer:
Subtraction and Division
Step-by-step explanation:
2x+8=9
2x+8-8=9-8
2x=1
x=1/2
 
        
             
        
        
        
Answer: The probability is 6/15 or 40%
Step-by-step explanation: In your question, you said Isabelle's book collection has 15 books and in that collect she has 6 autobiographies. So they probability as a fraction is 6/15.