Answer:
Step-by-step explanation:
Answer:
x = -1.8
Step-by-step explanation:
-9x = 16.2
Divide each side by -9
-9x/-9 = 16.2/-9
x = -1.8
Answer:

Step-by-step explanation:
Part (a) the probability that two people have a birthday on the 9th of any month.
Neglecting leap year, there are 365 days in a year.
There are 12 possible 9th in months that make a year calendar.
If two people have birthday on 9th; P(1st person) and P(2nd person).

Part (b) the probability that two people have a birthday on the same day of the same month
P(2 people selected have birthday on the same day of same month) + P(2 people selected not having birthday on same day of same month) = 1
P(2 people selected not having birthday on same day of same month):

P(2 people selected have birthday on the same day of same month) 
Answer:
C. (5x - 1)(x + 8)
Step-by-step explanation:
In a factoring problem by hand, the common steps to solve would be the "AM" method, or (Add-Multiply). Simply stated, finding what adds to the x-coeficient and what multiplies to the constant. In this case, what adds to 39(x) and what multiplies to 8. Just reading that, we can see that there aren't any numbers that can do that, so we have to improvise. Set up the problem equal to something that it can factor into:
- <em>Multiply the 5 and -8</em> = -40: <em>this is what we will factor</em>
- <em>The factors with add to 39 are 40 and -1</em>.
- <em>Set up the problem:</em>

Now, we can fo the math:

8(5x - 1) + x(5x - 1)
<em>Factor (5x - 1) from this:</em>
(5x - 1)(x + 8)
And we have our answer.
Answer:
a = 7
Step-by-step explanation:
I think, what you need to do, is first understand how to find the mean of anything: It's quite simple, actually, just add up all the numbers, then divide that number by the number of numbers. So, let's put it in perspective:
10, 3, 4, a, 6, 9, 10
7 is the mean. 7 is the number of numbers.
If, to find the mean is: 10 + 3 + 4 + a + 6 + 9 + 10= 7a ÷ 7, then: 10 +3 + 4+ 6 + 9 +10= 42
42 plus what divided by 7 is the question now.
42 + a ÷ 7= 7
So, 7 times 7, that's 49 minus 42 and you've got your answer: 7