Answer:
x²-9=x²-3²=(x+3)(x-3)
Step-by-step explanation:
use formula
a²-b²=(a+b)(a-b)
Answer:
1) n = 39916800
2) n = 1663200
3) n = 330
Step-by-step explanation:
1) If the blue balls are distinguishable as are the red balls
Then you can arrange these balls in the following ways, we must use a permutation
In totally we have 11 balls, then
n = 11P11
2) If Blue balls are distinguishable, but the red balls are identical
In this case, we need to do a correction due to the red balls are identical and we cannot identify the difference when we interchange two red balls

3) If the balls of each color are indistinguishable
We proceed equal to the before case but we include a correction due to blue balls also

What we need to do is find the difference between the two numbers to find the difference in price and then figure out what the percent of 23.5 that is
23.50-18.80=4.7
now we'll set up a proportion
4.7 x
----- = -----
23.5 100
then cross multiply and divide
100×4.7=470/23.5=20
the percent of decrease is 20%
I hope I've helped!