Which expression has been simplified INCORRECTLY? * 1 point - (-9) = 9 - (+9) = -9 + (-9) = -9 + (+9) = -9

+ (+9) = -9  

Step-by-step explanation:

- (-9) = 9 A negative times a negative is a positive

- (+9) = -9   A negative times a positive is a negative

+ (-9) = -9  A positive times a negative is a negative

+ (+9) = -9 A positive time a positive is a positive

the answer   is 200

step-by-step explanation:

this is a problem about poisson probabilities.   i don't know if you've

already studied poisson distributions, or if you have a place to look

to read more about the subject.  

here's how you can see a poisson distribution coming.   when there are

a lot of events that may happen at any time (or any place), and when

you're counting how many of them happen at a particular time (or a

particular place), and each event is independent of the others, then

the result is a poisson distribution.   this is roughly true for the

chocolate chips; one chip being in a cookie has only a small effect on

the probability that another chip will be in the cookie.

once you know you have a poisson distribution, you know a lot.   there

is only one parameter to a poisson distribution, so if you know the

mean, you know everything.   the form of the distribution is

  probability of n chips = {[e^(-x)]*(x^n)} / (n! )