Plz help due today giving brainliest!

What is 3x-9-5x=-7 if you solve for x

deff fn [24]

3x-9-5x = -7

combine like terms -9-2x = -7

add 9 to both sides

-2x = 2

divide both sides by -2

x - 2/-2 = -1

x = -1

6 0

3 years ago

At what point of the curve y = cosh(x does the tangent have slope 2?

Dahasolnce [82]

The hyperbolic cos (cosh) is given by
cosh (x) = (e^x + e^-x) / 2
The slope of a tangent line to a function at a point is given by the derivative of that function at that point.
d/dx [cosh(x)] = d/dx[(e^x + e^-x) / 2] = (e^x - e^-x) / 2 = sinh(x)
Given that the slope is 2, thus
sinh(x) = 2
x = sinh^-1 (2) = 1.444

Therefore, the curve of y = cosh(x) has a slope of 2 at point x = 1.44

5 0

3 years ago

Which statement is valid when a circumscribed circle of an acute triangle is

Anni [7]

<h3>There are two answers: Choice C, Choice D</h3>

Explanation:

For any acute triangle, the center of the circle is always inside the triangle.

For any right triangle, the center of the circle is the midpoint of the hypotenuse. The hypotenuse is the diameter of the circle.

For any obtuse triangle, the center of the circle is outside the triangle.

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Let's look at the answer choices more closely

A. False. This is only true if we have a right triangle as mentioned earlier.

B. False. This describes an inscribed circle.

C. True. As stated earlier.

D. True. This is based on how the circumscribed triangle is defined. It is set up to be the circle that goes through all three vertex points of a triangle. In other words, it is the smallest circle to completely enclose the given triangle.

4 0

3 years ago

Find the surface area of a cylinder with a base diameter of 8ft and a height of 6ft. Write your answer in terms of pi, and be su

Ksju [112]

Given that diameter of the base of the cylinder = 8 ft

Given that height of the cylinder = 6 ft

We have to find the surface area of the cylinder in terms of pi.

So we need to use formula of surface area of the cylinder which is

$Area= 2\pi r(r+h)$

where h= height = 6

r= radius = diameter/2 = 8/2 = 4

Now plug these values into above formula

$Area= 2\pi *4(4+3)$

$Area= 2\pi *4(7)$

$Area= 2\pi *28$

$Area= 56\pi$

Hence final answer is

$Area= 56\pi$ square ft

3 0

3 years ago

Read 2 more answers

A personnel director in a particular state claims that the mean annual income is the same in one of the state's counties (Coun

Shalnov [3]

Answer:

a) The hypothesis that the mean annual income is the same could not be rejected. There is no enough evidence to claim they are different.

b) The critical values for this two-sided test are t=±1.711.

Step-by-step explanation:

The question is incomplete:

(a) Identify the claim and state H0 and Ha.

Which is the correct claim below?

(b) Find the critical value(s) and identify the rejection region(s).

Enter the critical value(s) below.

We have an hypothesis test on the difference of two means.

The null and alternative hypothesis are:

$H_0: \mu_a-\mu_b=0\\\\H_a: \mu_a-\mu_b\neq 0$

The claim of the alternative hypothesis is that the mean annual income is different in County A and County B.

The null hypothesis is that the mean annual income is equal in both counties.

The significance level is α=0.10.

The sample from County A has a mean of S40,400, a s.d. of $8,700 and a sample size of 18 residents.

The sample from County B has a mean of S39,200, a s.d. of $6,000 and a sample size of 8 residents.

The standard error of the difference of means is:

$\sigma_d=\sqrt{\frac{\sigma_a^2}{n_a}+\frac{\sigma_b^2}{n_b}}=\sqrt{\frac{8700^2}{18}+\frac{6000^2}{8}}=\sqrt{8705000}=2950$

The degrees of freedom are:

$df=n_a+n_b-2=18+8-2=24$

Then, the test statistic is:

$t=\frac{\Delta M-\Delta \mu}{\sigma_d} =\frac{(40,400-39,200)-0}{2950} =\frac{1200}{2950}=0.407$

For a statistic t=0.407, and df=24, the P-value is P=0.69. As the P-value is bigger than the significance level, the null hypothesis failed to be rejected.

If we would use the critial value approach, we would have to calculate the critical values for t, for df=24, two sided test and α=0.10.

The critical values, looking in a table, are t=1.711.

5 0

3 years ago