Please help me I really need this
2 answers:
Answer:
8C5 = 56
Step-by-step explanation:
The formula for nCk is ...
nCk = n!/(k!(n-k)!)
Then the value of 8C5 is ...
8!/(5!(8-5)!) = 8·7·6/(3·2·1) = 8·7
8C5 = 56
_____
<em>Additional comment</em>
The larger of the denominator factorials will cancel most of the factors of the numerator. The remaining denominator factors can be factored from the remaining numerator values to simplify the problem of doing the math by hand. Most graphing calculators and all spreadsheets can compute this function for you.
You might be interested in
Answer:
Step-by-step explanation:
We are given the second derivative:
And we want to find its inflection points.
To do so, we will first determine possible inflection points. These occur whenever g''(x) = 0 or is undefined.
Next, we will test values for the intervals. Inflection points occur if and only if the sign changes before and after the point.
So first, finding the zeros, we see that:
So, we can draw the following number-line:
<----(-4)--------------(3)----(6)---->
Now, we will test values for the intervals x < -4, -4 < x < 3, 3 < x < 6, and x > 6.
Testing for x < -4, we can use -5. So:
Since we acquired a positive result, g(x) is concave up for x < -4.
For -4 < x < 3, we can use 0. So:
Since we acquired a negative result, g(x) is concave down for -4 < x < 3.
And since the sign changed before and after the possible inflection point at x = -4, x = -4 is indeed an inflection point.
For 3 < x < 6, we can use 4. So:
Since we acquired a negative result, g(x) is concave down for 3 < x < 6.
Since the sign didn't change before and after the possible inflection point at x = 3 (it stayed negative both times), x = -3 is not a inflection point.
And finally, for x > 6, we can use 7. So:
So, g(x) is concave up for x > 6.
And since we changed signs before and after the inflection point at x = 6, x = 6 is indeed an inflection point.
Hi there! :)
Find the perimeter by solving for y.
We know that a rectangle contains two pairs of parallel and congruent sides, therefore:
5y - 1 = 2y + 8
We can solve for y using this expression. Begin by subtracting 2y from both sides:
5y - 2y - 1 = 2y - 2y + 8
3y - 1 = 8
Add 1 to both sides:
3y - 1 + 1 = 8 + 1
3y = 9
Divide both sides by 3:
y = 3
Recall that the perimeter of a rectangle is:
P = 2l + 2w
Plug in the given expressions for the side lengths to find one equation:
P = 2(5y - 1) + 2(y - 1)
Simplify by distribution:
P = 10y - 2 + 2y - 2
Combine like terms:
P = 12y - 4
Plug in the solved value of y into this equation:
P = 12(3) - 4
P = 36 - 4
P = 32 cm.