First draw p yellow = 4/7
2nd draw p red = 3/7
3rd draw p red = 3/7
To find the probability of this event (1yellow 2 red - with replacement) we multiply the probabilities.
4/7 x 3/7 x3/7 = 36/343 which cannot be reduced further
679, 587, 852,600,346,847,849,658,864
or
6.7958785e+26
Let the no. of stars one can expect to see at Bryce Canyon be x.
Given that : No. of stars visible in the night sky = 2000
Also, given that, it is 4/15 of x.
Now, we have

∴ You can expect to see 7,500 stars at Bryce Canyon.
3(3x+4)(2x+5)
Because you factor out the 3 and then factor 6x^2+23x+20
That becomes (6x^2+8x)+(15x+20)
Factor out a two from the left and five from the right.
That makes 2x(3x+4) + 5(3x+4)
That becomes (3x+4)(2x+5)
Then put the three back in front.