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4 years ago

Can u help me step by step need to fill in the blanks

Mathematics

2 answers:

Rina8888 [55]4 years ago

6 0

-18a+17b is the answer because you multiply by -1 to each

Vika [28.1K]4 years ago

3 0

The minus sign outside of the parentheses can actually be represented with -1 instead.

this means that you must distribute (multiply) -1 by the numbers inside of the parentheses.

keep in mind that when you multiply the -1 by the 2nd number inside, and the operation is subtract, instead of 17b, it would be -17b.

-1 • 18a = -18a
-1 • -17b = -17b

the final answer would be -18a + 17b :)

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To qualify for a police academy, candidates must score in the top 10% on a general abilities test. The test has a mean of 200 an

kolbaska11 [484]

Answer:

z = 1.28 < a - 200/20

And if we solve for a we got

a = 200 + 1.28 * 20 = 225.6

So the value of height that separates the bottom 90% of data from the top 10% is 225.6.

Step-by-step explanation:

Let X the random variable that represent the scores of a population, and for this case we know the distribution for X is given by:

X ~ N (200,20)

For u = 200 and o = 20

For this case we can use the z score in order to solve this problem, given by this formula:

Z = x-u/o

For this part we want to find a value a, such that we satisfy this condition:

P (X > a) = 0.1 (a)

P (X < a) = 0.9 (b)

Both conditions are equivalent on this case. We can use the z score again in order to find the value a.

As we can see on the figure attached the z value that satisfy the condition with 0.9 of the area on the left and 0.1 of the area on the right it's z=1.28. On this case P(Z<1.28)=0.9 and P(z>1.28)=0.1

If we use condition (b) from previous we have this:

P ( X < a) = P (X-u/o < a - u/o) = 0.9

P (z < a-u/o) = 0.9

But we know which value of z satisfy the previous equation so then we can do this:

z = 1.28 < a - 200/20

And if we solve for a we got

a = 200 + 1.28 * 20 = 225.6

So the value of height that separates the bottom 90% of data from the top 10% is 225.6.

3 0

3 years ago

Question 6 (5 points)

Studentka2010 [4]

Answer:

30 inches

Step-by-step explanation:

using a^2+b^2=c^2

72^2=5184

30^2=900

5184+900=6084

√6084=78

3 0

3 years ago

How do you <br>convert 7/5 into a decimal and round to the nearest hundreth

Amanda [17]

7/5 is an improper fraction. we need to change it to a mixed number:
7/5 -> 1 2/5

now, we know that 1/5 is 0.2 so that means 2/5 must be 0.4. there also is a 1 so the answer is going to be 1.4

The answer (rounding to the 100th place) is 1.4

:)

4 0

4 years ago

What is the value of b in the equation (y Superscript b Baseline) Superscript 4 Baseline = StartFraction 1 Over y Superscript 24

shusha [124]

The value of b is -6.

Explanation:

The expression is $\left(y^{b}\right)^{4}=\frac{1}{y^{24}}$

To determine the value of b, we shall solve the expression.

Applying exponent rule, $\left(a^{b}\right)^{c}=a^{b c}$ , we get,

$y^{4b}=\frac{1}{y^{24}}$

Applying exponent rule, $\frac{1}{a^{b}}=a^{-b}$ , we have,

$y^{4b}=y^{-24}$

The expression is of the form, $a^{f(x)}=a^{g(x)}$ then $f(x)=g(x)$

Applying this rule, we get,

$4b=-24$

Dividing both sides by 4, we have,

$b=-6$

Hence, the value of b is -6.

4 0

3 years ago

Read 2 more answers

Find the exact value of cos(sin^-1(-5/13))

son4ous [18]

bearing in mind that the hypotenuse is never negative, since it's just a distance unit, so if an angle has a sine ratio of -(5/13) the negative must be the numerator, namely -5/13.

$\bf cos\left[ sin^{-1}\left( -\cfrac{5}{13} \right) \right] \\\\[-0.35em] ~\dotfill\\\\ \stackrel{\textit{then we can say that}~\hfill }{sin^{-1}\left( -\cfrac{5}{13} \right)\implies \theta }\qquad \qquad \stackrel{\textit{therefore then}~\hfill }{sin(\theta )=\cfrac{\stackrel{opposite}{-5}}{\stackrel{hypotenuse}{13}}}\impliedby \textit{let's find the \underline{adjacent}}$

$\bf \textit{using the pythagorean theorem} \\\\ c^2=a^2+b^2\implies \pm\sqrt{c^2-b^2}=a \qquad \begin{cases} c=hypotenuse\\ a=adjacent\\ b=opposite\\ \end{cases} \\\\\\ \pm\sqrt{13^2-(-5)^2}=a\implies \pm\sqrt{144}=a\implies \pm 12=a \\\\[-0.35em] ~\dotfill\\\\ cos\left[ sin^{-1}\left( -\cfrac{5}{13} \right) \right]\implies cos(\theta )=\cfrac{\stackrel{adjacent}{\pm 12}}{13}$

le's bear in mind that the sine is negative on both the III and IV Quadrants, so both angles are feasible for this sine and therefore, for the III Quadrant we'd have a negative cosine, and for the IV Quadrant we'd have a positive cosine.

8 0

3 years ago