Anyone good at 8th grade math please help out

Answer:

8 days

Step-by-step explanation:

1 ton=2,000 pounds and If you divide 2,000÷250=8 days. It will talk 8 days for the baby whale to weigh his first ton.

Answer:

7.3

Step-by-step explanation:

Biggest value = 8.9

smallest value = 1.6

range = 8.9-1.6 = 7.3

Step-by-step explanation:

range=highest number - lowest number

= 8.9 - 1.6

=7.3

Answer:

[tex]y = \frac{-1}{5}x -4[/tex]

Step-by-step explanation:

[tex]x + 5y = -20\\\\5y = -x - 20\\\\y = \frac{-1}{5}x - 4[/tex]

Answer: C 22.5 ft2!

Step-by-step explanation:

i took the test, have a great day:) <3

Answer:

right

Step-by-step explanation:

Answer:

Quesiton is not clear. here is the asnswer basing on our understand

Step-by-step explanation:

(8-32)3 = (-24*3) = =72

Answer:

A. 8100

Step-by-step explanation:

85 x 86

To estimate, we multiply 85*100, which is the easiest multiplication, as a multiplication by 100 is the same as placing two zeros at the end of the number.

85*100 = 8500

Since 86 < 100, 85*86 < 8500. Thus, the correct estimate is given by option A.

y = -49

multiply 7 on both sides

-7*7 = y/7*7

-49 = y

Answer:

y = -49

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

Equality Properties

Step-by-step explanation:

Step 1: Define

Identify

-7 = y/7

Step 2: Solve for y

Answer:

92 dB

Step-by-step explanation:

Fsf

Answer:

[tex]volume = base \: area \times height \\ = 36 \times 8 \\ = 288 \: cubic \: inches[/tex]

Answer:

hope it helps uh

Answer:

62 degrees since there are supplementary angles

Step-by-step explanation:

∠PQO= 180 degrees - 118 degrees

∠PQO= 62 degrees is the answer.

∠PQO= 180°-∠RQO -------(Supplementary Angles)

∠PQO= 180° - 118°

∠PQO= 62° answer.

Answer:

(x-4)(x+4)

Step-by-step explanation:

x^2 - 64 = x^2 - 4^2 = (x-4)(x+4)

Answer:

20000000000000000000000000000

Answer:

Step-by-step explanation:

1). If two right triangles are congruent by HL property of congruence,

   Their corresponding sides will be congruent.

   By this property,

   x - 4 = y + 3

   x - y = 7 -----(1)

   x = 2y ------(2)

   By substituting x = 2y in equation (1),

   2y - y = 7

    y = 7

    From equation (1)

    x - 7 = 7

    x = 15

2). If both the right triangles are congruent by HL property of congruence,

    Their height and and hypotenuse will be congruent.

    y + x = x + 7

    y = 7

    y + 5 = 2y - x

    y - 2y + 5 = -x

    -y + 5 = -x

    x = y - 5

    By substituting y = 7 in the equation,

    x = 7 - 5

    x = 2

Answer:

The 95% confidence interval for the proportion of respondents who say the internet has strengthened their relationship with family and friends is [tex](0.67 - 1.96\sqrt{\frac{0.67*0.33}{n}}, 0.67 + 1.96\sqrt{\frac{0.67*0.33}{n}})[/tex], in which n is the size of the sample.

Step-by-step explanation:

In a sample with a number n of people surveyed with a probability of a success of [tex]\pi[/tex], and a confidence level of [tex]1-\alpha[/tex], we have the following confidence interval of proportions.

[tex]\pi \pm z\sqrt{\frac{\pi(1-\pi)}{n}}[/tex]

In which

z is the z-score that has a p-value of [tex]1 - \frac{\alpha}{2}[/tex].

67% of internet users said the internet has generally strengthened their relationship with family and friends.

This means that [tex]\pi = 0.67[/tex]

95% confidence level

So [tex]\alpha = 0.05[/tex], z is the value of Z that has a p-value of [tex]1 - \frac{0.05}{2} = 0.975[/tex], so [tex]Z = 1.96[/tex].

The lower limit of this interval is:

[tex]\pi - z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.67 - 1.96\sqrt{\frac{0.67*0.33}{n}}[/tex]

The upper limit of this interval is:

[tex]\pi + z\sqrt{\frac{\pi(1-\pi)}{n}} = 0.67 + 1.96\sqrt{\frac{0.67*0.33}{n}}[/tex]

The 95% confidence interval for the proportion of respondents who say the internet has strengthened their relationship with family and friends is [tex](0.67 - 1.96\sqrt{\frac{0.67*0.33}{n}}, 0.67 + 1.96\sqrt{\frac{0.67*0.33}{n}})[/tex], in which n is the size of the sample.

Answer:

2 is the probability

Step-by-step explanation:

Answer:

the answer is 8,000.

Step-by-step explanation:

9514 1404 393

Answer:

  a = 6, b = 12, c = 6, d = 6√3

Step-by-step explanation:

The two triangles are the "special" triangles.

The 45-45-90 triangle has side lengths in the ratios 1 : 1 : √2.

The 30-60-90 triangle has side lengths in the ratios 1 : √3 : 2.

Then ...

  c : a : 6√2 = 1 : 1 : √2   ⇒   c = a = 6

and ...

  a : d : b = 1 : √3 : 2   ⇒   d = 6√3 and b = 12 . . . (since a=6)

The lengths are ...

  a = 6, b = 12, c = 6, d = 6√3

Answer:

w=-1+[tex]\sqrt{2}[/tex], w=-1-[tex]\sqrt{2}[/tex]

Step-by-step explanation:

Answer:

yay

Step-by-step explanation:

Answer:

7kg

Step-by-step explanation:

258 / 36 = 7.16

the nearest ten, 7.20

Mark me brianest

Answer:

y = mx + b

m =(-2--4)/(-6--7)

m = 2

-2 = 2(-6) +b

b = 10

y= 2x + 10

Answer: c

Step-by-step explanation: because yes

Answer:

d po answer

yan po sinagot ko

hehe

refer to the attachment

Answer:

the equation is 11+1.2d= h      so the height after 9 days would be 21.8cm

Step-by-step explanation:

Answer:

f(h) = 11 + 1.2h

f(9) = 21.8 cm

Step-by-step explanation:

let 'h' = height

f(h) = 11 + 1.2h

height after 9 days:

f(9) = 11 + 1.2(9)

= 11 + 10.8

= 21.8 cm

Answer:

[tex]A + B + E = 32[/tex]

Step-by-step explanation:

Given

[tex]\int\limits {x^2\cdot e^{-4x}} \, dx = -\frac{1}{64}e^{-4x}[Ax^2 + Bx + E]C[/tex]

Required

Find [tex]A +B + E[/tex]

We have:

[tex]\int\limits {x^2\cdot e^{-4x}} \, dx = -\frac{1}{64}e^{-4x}[Ax^2 + Bx + E]C[/tex]

Using integration by parts

[tex]\int {u} \, dv = uv - \int vdu[/tex]

Where

[tex]u = x^2[/tex] and [tex]dv = e^{-4x}dx[/tex]

Solve for du (differentiate u)

[tex]du = 2x\ dx[/tex]

Solve for v (integrate dv)

[tex]v = -\frac{1}{4}e^{-4x}[/tex]

So, we have:

[tex]\int {u} \, dv = uv - \int vdu[/tex]

[tex]\int\limits {x^2\cdot e^{-4x}} \, dx = x^2 *-\frac{1}{4}e^{-4x} - \int -\frac{1}{4}e^{-4x} 2xdx[/tex]

[tex]\int\limits {x^2\cdot e^{-4x}} \, dx = -\frac{x^2}{4}e^{-4x} - \int -\frac{1}{2}e^{-4x} xdx[/tex]

[tex]\int\limits {x^2\cdot e^{-4x}} \, dx = -\frac{x^2}{4}e^{-4x} +\frac{1}{2} \int xe^{-4x} dx[/tex]

-----------------------------------------------------------------------

Solving

[tex]\int xe^{-4x} dx[/tex]

Integration by parts

[tex]u = x[/tex] ---- [tex]du = dx[/tex]

[tex]dv = e^{-4x}dx[/tex] ---------- [tex]v = -\frac{1}{4}e^{-4x}[/tex]

So:

[tex]\int xe^{-4x} dx = -\frac{x}{4}e^{-4x} - \int -\frac{1}{4}e^{-4x}\ dx[/tex]

[tex]\int xe^{-4x} dx = -\frac{x}{4}e^{-4x} + \int e^{-4x}\ dx[/tex]

[tex]\int xe^{-4x} dx = -\frac{x}{4}e^{-4x} -\frac{1}{4}e^{-4x}[/tex]

So, we have:

[tex]\int\limits {x^2\cdot e^{-4x}} \, dx = -\frac{x^2}{4}e^{-4x} +\frac{1}{2} \int xe^{-4x} dx[/tex]

[tex]\int\limits {x^2\cdot e^{-4x}} \, dx = -\frac{x^2}{4}e^{-4x} +\frac{1}{2} [ -\frac{x}{4}e^{-4x} -\frac{1}{4}e^{-4x}][/tex]

Open bracket

[tex]\int\limits {x^2\cdot e^{-4x}} \, dx = -\frac{x^2}{4}e^{-4x} -\frac{x}{8}e^{-4x} -\frac{1}{8}e^{-4x}[/tex]

Factor out [tex]e^{-4x}[/tex]

[tex]\int\limits {x^2\cdot e^{-4x}} \, dx = [-\frac{x^2}{4} -\frac{x}{8} -\frac{1}{8}]e^{-4x}[/tex]

Rewrite as:

[tex]\int\limits {x^2\cdot e^{-4x}} \, dx = [-\frac{1}{4}x^2 -\frac{1}{8}x -\frac{1}{8}]e^{-4x}[/tex]

Recall that:

[tex]\int\limits {x^2\cdot e^{-4x}} \, dx = -\frac{1}{64}e^{-4x}[Ax^2 + Bx + E]C[/tex]

[tex]\int\limits {x^2\cdot e^{-4x}} \, dx = [-\frac{1}{64}Ax^2 -\frac{1}{64} Bx -\frac{1}{64} E]Ce^{-4x}[/tex]

By comparison:

[tex]-\frac{1}{4}x^2 = -\frac{1}{64}Ax^2[/tex]

[tex]-\frac{1}{8}x = -\frac{1}{64}Bx[/tex]

[tex]-\frac{1}{8} = -\frac{1}{64}E[/tex]

Solve A, B and C

[tex]-\frac{1}{4}x^2 = -\frac{1}{64}Ax^2[/tex]

Divide by [tex]-x^2[/tex]

[tex]\frac{1}{4} = \frac{1}{64}A[/tex]

Multiply by 64

[tex]64 * \frac{1}{4} = A[/tex]

[tex]A =16[/tex]

[tex]-\frac{1}{8}x = -\frac{1}{64}Bx[/tex]

Divide by [tex]-x[/tex]

[tex]\frac{1}{8} = \frac{1}{64}B[/tex]

Multiply by 64

[tex]64 * \frac{1}{8} = \frac{1}{64}B*64[/tex]

[tex]B = 8[/tex]

[tex]-\frac{1}{8} = -\frac{1}{64}E[/tex]

Multiply by -64

[tex]-64 * -\frac{1}{8} = -\frac{1}{64}E * -64[/tex]

[tex]E = 8[/tex]

So:

[tex]A + B + E = 16 +8+8[/tex]

[tex]A + B + E = 32[/tex]

Answer:

a) The null hypothesis is [tex]H_0: \mu = 310[/tex] and the alternative hypothesis is [tex]H_1: \mu < 310[/tex].

b) The test statistic is [tex]t = -1.54[/tex]. The critical value is [tex]t_c = -2.473[/tex].

c) The test statistic is [tex]t = -1.54 < t_c = -2.473[/tex], which means that there is not enough evidence to reject the null hypothesis that the mean transaction time is of 310 times, so no evidence to conclude that the mean transaction time is less than 310 seconds.

Step-by-step explanation:

Question a:

Costco is interested in finding out whether the mean transaction time is less than 310 seconds.

At the null hypothesis, we test if the mean is of 310 seconds, that is:

[tex]H_0: \mu = 310[/tex]

At the alternative hypothesis, we test if the mean is of less than 310 seconds, that is:

[tex]H_1: \mu < 310[/tex]

b) Find the test statistic and the critical value at 1% significance level.

Test if the mean is less than a value, sample of 28, and standard deviation for the sample. Thus, we have a left-tailed t-test with 28 - 1 = 27 degrees of freedom and a 0.01 significance level, and the critical value is [tex]t_c = -2.473[/tex].

The test statistic is:

[tex]t = \frac{X - \mu}{\frac{s}{\sqrt{n}}}[/tex]

In which X is the sample mean, [tex]\mu[/tex] is the value tested at the null hypothesis, s is the standard deviation pf the sample and n is the size of the sample.

310 is tested at the null hypothesis:

This means that [tex]\mu = 310[/tex].

A sample of 28 sales transactions at Costco shows a mean transaction time of 296 seconds with a standard deviation of 48 seconds.

This means that [tex]n = 28, X = 296, s = 48[/tex].

Value of the test statistic:

[tex]t = \frac{X - \mu}{\frac{s}{\sqrt{n}}}[/tex]

[tex]t = \frac{296 - 310}{\frac{48}{\sqrt{28}}}[/tex]

[tex]t = -1.54[/tex]

The test statistic is [tex]t = -1.54[/tex].

c) At 1% level of significance, what is your conclusion

The test statistic is [tex]t = -1.54 < t_c = -2.473[/tex], which means that there is not enough evidence to reject the null hypothesis that the mean transaction time is of 310 times, so no evidence to conclude that the mean transaction time is less than 310 seconds.

Answer:

A) 91

Step-by-step explanation:

Supplementary angels are 2 angels whos sum is 180

To find the supplement of angle 89, substract 89 from 180

180-89 = x

91 = x

Answer:

$200.33

Step-by-step explanation:

Total amount paid = $222.36

Wrapping charge = $4

Sales tax = 9%

The price would be:

Cost + sales tax amount = (Total amount paid - wrapping charge)

Cost + sales tax amount = (222.36 - 4)

Cost + sales tax = 218. 36

Subtracting the sales tax :

Let cost = x

x + 0.09x = 218. 36

1.09x = 218.36

x = 218.36 / 1.09

x = $200.33