CF = CD + DF (since D is simply a point on the line, and C to that point added onto F to that point is CF), so 4y-9+2y-7=14. Adding it up, we get 6y-16=14 and adding by 16 we get 30=6y. Dividing both sides by 6, we get y=5. Plugging that into DF, we get 10-7=DF=3
2/5
Since 12 out of 30 marbles were black, you can assume that the percentage of black marbles in the bag is 40% (Ex: 12/30=.4) The probability that the marble you pick is black is equal to the percentage of black marbles in the bag. 40% is equal to 2/5.
It would be mean. The mean is the average that is you are looking for, since she wants a summerization of all the values in the data set. To find the mean (average) add all the numbers and then divide by the amount of numbers.
Answer: Option (2)
Step-by-step explanation:
The inverse of a function swaps the domain and range.