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2 years ago

What is 2x-15+21= -18

Mathematics

2 answers:

Brrunno [24]2 years ago

7 0

Hopes this helps:

Answer: x = -12

How I know I use this app called Cymath.

kirill115 [55]2 years ago

4 0

Answer:

2x - 15 +21 = -18

2x + 6 + 18 = 0

2x + 24 =0 ...it is a linear equation

if u want to solve for X then..

2x = -24

X = - 24

X = -12

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A flock of birds was flying around a tree. When they landed, three birds to a branch, no branches were left and one bird had to

trapecia [35]

Answer: 5 branches and 16 birds.

Step-by-step explanation:

If the number of birds is B, and the number of branches is N.

First we have the equation:

B = 3*N + 1

(3 birds per branch + 1 that was flying around)

for the second equation we have:

B = 4*(N - 1)

(4 birds per branch, but one branch had no birds on it, so there are N -1 branches used)

now we can write:

3*N + 1 = 4*(N - 1)

3*N + 1 = 4*N - 4

4 + 1 = 4*N - 3*N

5 = N

So we had 5 branches, now we can replace it in one of the equations and find the number of birds.

B = 3*N + 1 = 3*5 + 1 = 16

6 0

3 years ago

Read 2 more answers

A wave has frequency of 10 Hz and a speed of 30 m/s. What is the wavelength of the wave?

ladessa [460]

Answer:

Step-by-step explanation:

Wavelength is usually denoted as letter lambda (λ); it is equal to the speed (v) of a wave train in a medium divided by its frequency (f): λ = v/f. Waves of different wavelengths.

formula: λ = v/f

solution: λ= 30m/s / 10Hz

= 3

8 0

3 years ago

PLEASE HELP WILL CROWNNNNNN!!!!!

Serga [27]

Answer:

- 3

- 8

Step-by-step explanation:

f ( - 2 )

= 2 - 5 ( - 2 )

= 2 - ( - 10 )

= 2 + 10

= 12

f ( - 1 )

= 2 - 5 ( - 1 )

= 2 - ( - 5 )

= 2 + 5

= 7

f ( 0 )

= 2 - 5 ( 0 )

= 2

f ( 1 )

= 2 - 5 ( 1 )

= 2 - 5

= - 5 + 2

= - 3

f ( 2 )

= 2 - 5 ( 2 )

= 2 - 10

= - 10 + 2

= - 8

6 0

3 years ago

find the area of the window 24inch by 30inch and convert in to square feet, round the anwser to the second decimal place

Nezavi [6.7K]

Answer:

5 sq. ft.

Step-by-step explanation:

To find the area of a rectangle, use this formula: A = lw.

Because you know two side lengths of the window, you can just plug in the numbers to the formula.

But not yet! You need to convert the given lengths into feet first.

You know that there are 12 inches in 1 foot.

So:

24 inches ÷ 12 inches/foot = 2 feet

30 inches ÷ 12 inches/foot = 2.5 feet

Alright, now you can plug in these lengths into the formula.

A = (2) (2.5) = 5 sq. ft.

The question asks you to round, but there is nothing to round, so you are done here.

4 0

3 years ago

Two major automobile manufacturers have produced compact cars with engines of the same size. We are interested in determining wh

Molodets [167]

Answer:

(A) The mean for the differences is 2.0.

(B) The test statistic is 1.617.

(C) At 90% confidence the null hypothesis should not be rejected.

Step-by-step explanation:

We are given that a random sample of eight cars from each manufacturer is selected, and eight drivers are selected to drive each automobile for a specified distance.

The following data (in miles per gallon) show the results of the test;

Driver Manufacturer A Manufacturer B

1 32 28

2 27 22

3 26 27

4 26 24

5 25 24

6 29 25

7 31 28

8 25 27

Let $\mu_1$ = mean MPG for the fuel efficiency of Manufacturer A brand

$\mu_2$ = mean MPG for the fuel efficiency of Manufacturer B brand

SO, Null Hypothesis, $H_0$ : $\mu_1-\mu_2=0$ or $\mu_1= \mu_2$ {means that there is a not any significant difference in the mean MPG (miles per gallon) when testing for the fuel efficiency of these two brands of automobiles}

Alternate Hypothesis, $H_A$ : $\mu_1-\mu_2\neq 0$ or $\mu_1\neq \mu_2$ {means that there is a significant difference in the mean MPG (miles per gallon) for the fuel efficiency of these two brands of automobiles}

The test statistics that will be used here is Two-sample t test statistics as we don't know about the population standard deviations;

T.S. = $\frac{(\bar X_1-\bar X_2)-(\mu_1-\mu_2)}{s_p\sqrt{\frac{1}{n_1}+\frac{1}{n_2} } }$ ~ $t__n__1+_n__2-2$

where, $\bar X_1$ = sample mean MPG for manufacturer A = $\frac{\sum X_A}{n_A}$ = 27.625

$\bar X_2$ = sample mean MPG for manufacturer B = $\frac{\sum X_B}{n_B}$ = 25.625

$s_1$ = sample standard deviation for manufacturer A = $\sqrt{\frac{\sum (X_A-\bar X_A)^{2} }{n_A-1} }$ = 2.72

$s_2$ = sample standard deviation manufacturer B = $\sqrt{\frac{\sum (X_B-\bar X_B)^{2} }{n_B-1} }$ = 2.20

$n_1$ = sample of cars selected from manufacturer A = 8

$n_2$ = sample of cars selected from manufacturer B = 8

Also, $s_p=\sqrt{\frac{(n_1-1)s_1^{2}+(n_2-1)s_2^{2} }{n_1+n_2-2} }$ = $\sqrt{\frac{(8-1)\times 2.72^{2}+(8-1)\times 2.20^{2} }{8+8-2} }$ = 2.474

(A) The mean for the differences is = 27.625 - 25.625 = 2

(B) The test statistics = $\frac{(27.625-25.625)-(0)}{2.474 \times \sqrt{\frac{1}{8}+\frac{1}{8} } }$ ~ $t_1_4$

= 1.617

(C) Now at 10% significance level, the t table gives critical values between -1.761 and 1.761 at 14 degree of freedom for two-tailed test. Since our test statistics lies within the range of critical values of t, so we have insufficient evidence to reject our null hypothesis as it will not fall in the rejection region due to which we fail to reject our null hypothesis.

Therefore, we conclude that there is a not any significant difference in the mean MPG (miles per gallon) when testing for the fuel efficiency of these two brands of automobiles.

5 0

3 years ago

What is 2x-15+21= -18​

What is 2x-15+21= -18