Set up the two events A = first card is a 9 B = second card is a 9
The probability for event A is P(A) = 4/52 because there are four "9" cards out of 52 total
If event A happens first, and B follows, then the probability is P(B|A) = 3/51 because there are 3 nines left over out of 52-1 = 51 total left over No replacement has been made The notation P(B|A) means "probability of event B given that event A has happened"
Multiply the probabilities P(A and B) = P(A)*P(B|A) P(A and B) = (4/52)*(3/51) P(A and B) = (4*3)/(52*51) P(A and B) = 12/2652 P(A and B) = 1/221 P(A and B) = 0.00452488687782
Rounded to 4 decimal places, the approximate answer is 0.0045 The exact answer as a fraction is 1/221
Let f(x) be y so you have y=7x-13 Reverse the signs of x and y so you have x=7y-13 And then find the value of y x+13=7y (x+13)/7=y And change y to f(x)-1
