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3 years ago

Solve it by substitution method:- 5x - 6y=-9 and 3x + 4y= 25

1 answer:

8 0

$\left\{\begin{array}{ccc}-5x-6y=-9&/\cdot2\\3x+4y=25&/\cdot3\end{array}\right\\+\left\{\begin{array}{ccc}-10x-12y=-18\\9x+12y=75\end{array}\right\\------------\\.\ \ \ \ \ \ \ -x=57\\.\ \ \ \ \ \ \ \ \ x=-57\\\\3\cdot(-57)+4y=25\\-171+4y=25\\4y=25+171\\4y=196\ \ \ \ /:4\\y=49\\\\Solution:x=-57;\ y=49.$

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Persons having Raynaud's syndrome are apt to suffer a sudden impairment of blood circulation in fingers and toes. In an experime

Citrus2011 [14]

Answer:

There is enough evidence to say that the true average heat output of persons with the syndrmoe differs from the true average heat output of non-sufferers.

Step-by-step explanation:

We have to perform a hypothesis test on the difference between means.

The null and alternative hypothesis are:

$H_0: \mu_1-\mu_2=0\\\\H_a: \mu_1-\mu_2$

μ1: mean heat output for subjects with the syndrome.

μ2: mean heat output for non-sufferers.

We will use a significance level of 0.05.

The difference between sample means is:

$M_d=\bar x_1-\bar x_2=0.63-2.09=-1.46$

The standard error is

$s_{M_d}=\sqrt{\sigma_1^2/n_1+\sigma_2^2/n_2}=\sqrt{0.3^2/9+0.5^2/9}=\sqrt{ 0.038 } \\\\ s_{M_d}=0.194$

The t-statistic is

$t=\dfrac{M_d}{s_{M_d}}=\dfrac{-1.46}{0.194}=-7.52$

The degrees of freedom are

$df=n_1+n_2-2=9+9-2=16$

The critical value for a left tailed test at a significance level of 0.05 and 16 degrees of freedom is t=-1.746.

The t-statistic is below the critical value, so it lies in the rejection region.

The null hypothesis is rejected.

There is enough evidence to say that the true average heat output of persons with the syndrmoe differs from the true average heat output of non-sufferers.

5 0

2 years ago

Need help quickly! Thanks

Rzqust [24]

Answer:

y = $-2^x$

Step-by-step explanation:

If the equation of a function is in the form of y = h(x)

When the graph of this function is reflected across x-axis,

Transformed function will be,

y = -h(x)

Further reflected across y-axis, then the transformed function will be,

y = -h(-x)

By this rule,

Given equation when reflected across x-axis,

y = $-(\frac{1}{2})^{x}$

Further reflected across y-axis,

y = $-(\frac{1}{2})^{-x}$

y = $-(2^{-1})^x$

y = $-2^x$

5 0

2 years ago

Is 4/2 + 5/2 a rational or irrational number

sesenic [268]

As both 4/2 and 5/2 are rational Numbers and Sum of rationals is a Rational Number.
Therefore, 9/2 is a Rational Number.

6 0

2 years ago

Read 2 more answers

A solid is formed by adjoining two hemispheres to the ends of a right circular cylinder. An industrial tank of this shape must h

mestny [16]

Answer:

Radius =6.518 feet

Height = 26.074 feet

Step-by-step explanation:

The Volume of the Solid formed = Volume of the two Hemisphere + Volume of the Cylinder

Volume of a Hemisphere $=\frac{2}{3}\pi r^3$

Volume of a Cylinder $=\pi r^2 h$

Therefore:

The Volume of the Solid formed

$=2(\frac{2}{3}\pi r^3)+\pi r^2 h\\\frac{4}{3}\pi r^3+\pi r^2 h=4640\\\pi r^2(\frac{4r}{3}+ h)=4640\\\frac{4r}{3}+ h =\frac{4640}{\pi r^2} \\h=\frac{4640}{\pi r^2}-\frac{4r}{3}$

Area of the Hemisphere = $2\pi r^2$

Curved Surface Area of the Cylinder = $2\pi rh$

Total Surface Area=

$2\pi r^2+2\pi r^2+2\pi rh\\=4\pi r^2+2\pi rh$

Cost of the Hemispherical Ends = 2 X Cost of the surface area of the sides.

Therefore total Cost, C

$=2(4\pi r^2)+2\pi rh\\C=8\pi r^2+2\pi rh$

Recall: $h=\frac{4640}{\pi r^2}-\frac{4r}{3}$

Therefore:

$C=8\pi r^2+2\pi r(\frac{4640}{\pi r^2}-\frac{4r}{3})\\C=8\pi r^2+\frac{9280}{r}-\frac{8\pi r^2}{3}\\C=\frac{9280}{r}+\frac{24\pi r^2-8\pi r^2}{3}\\C=\frac{9280}{r}+\frac{16\pi r^2}{3}\\C=\frac{27840+16\pi r^3}{3r}$

The minimum cost occurs at the point where the derivative equals zero.

$C^{'}=\frac{-27840+32\pi r^3}{3r^2}$

$When \:C^{'}=0$

$-27840+32\pi r^3=0\\27840=32\pi r^3\\r^3=27840 \div 32\pi=276.9296\\r=\sqrt[3]{276.9296} =6.518$

Recall:

$h=\frac{4640}{\pi r^2}-\frac{4r}{3}\\h=\frac{4640}{\pi*6.518^2}-\frac{4*6.518}{3}\\h=26.074 feet$

Therefore, the dimensions that will minimize the cost are:

Radius =6.518 feet

Height = 26.074 feet

5 0

2 years ago

Complete the phrases below using the word bank.

oee [108]

Answer:

A- b: the y value when y changes; the point where a line crosses the v-axis

B- m: What happens to y when x is one; the ratio of the y change to the x change

C- k: The y value when x is zero b x increases by one

Step-by-step explanation:

If this is about slope intercept form as i think it is

C sounds a little bonkers in this case though because when y is zero then x increases by one

7 0

2 years ago