What is eight equals negative two fifths c?

Ayudemen porfavor . Determine 4 ala potencia x + 4 ala potencia -x, si se sabe que 2ala potencia x + 2 ala potencia -x =3

Afina-wow [57]

Answer:

Es igual a 7.

Step-by-step explanation:

Ok, sabemos que:

$2^x + 2^{-x} = 3$

Queremos calcular:

$4^x + 4^{-x}$

Tambien sabemos que 4 = 2*2

Entonces:

$4^x + 4^{-x} = (2*2)^x + (2*2)^{-x}$

y sabemos que 2*2 = 2^2

Entonces:

$4^x + 4^{-x} = (2*2)^x + (2*2)^{-x} = (2^2)^x + (2^2)^{-x}$

y ahora podemos usar la relación:

$(a^n)^m = (a^m)^n = a^{m*n}$

entonces:

$(2^2)^x + (2^2)^{-x} = (2^x)^2 + (2^{-x})^2$

Ahora podemos completar cuadrados sumando y restando el termino:

$2*(2^x)*(2^{-x})$

Asi tendremos:

$(2^x)^2 + (2^{-x})^2 = (2^x)^2 + (2^{-x})^2 + 2*(2^x)*(2^{-x}) - 2*(2^x)*(2^{-x}) = (2^x + 2^{-x})^2 - 2*(2^x)*(2^{-x})$

Entonces de momento tenemos que:

$4^x + 4^{-x} = (2^x + 2^{-x})^2 - 2*(2^x)*(2^{-x})$

Sabemos que el termino que esta dentro del parentesis es igual a 3.

Y tambien podemos usar la propiedad:

$a^n*a^m = a^{n + m}$

en el termino de la derecha.

Asi tendremos:

$(2^x + 2^{-x})^2 - 2*(2^x)*(2^{-x}) = (3)^2 - 2*2^{x + (-x)} = 9 - 2 = 7$

7 0

2 years ago

X+2y=6 and x-y=3 solve by linear equations by substitution

nevsk [136]

X+2y=6
x-y=3x=6-2y
x=3+y

6-2y=3+y
3=3y
y=1

x=3+1
x=4
Answer: (4;1)

3 0

3 years ago

A group of eight individuals with high cholesterol levels were given a new drug that was designed to lower cholesterol levels. C

noname [10]

Answer:

Step-by-step explanation:

The data in the question is not well arranged. The correct arrangement is:

Before After difference

283 215

299 206

274 187

284 212

248 178

275 212

293 192

277 196

Solution:

a) This is a matched pair design/experiment. This is so because the measurement of cholesterol levels were carried out on the same individuals.

b) Corresponding cholesterol levels before and after treatment form matched pairs.

The data for the test are the differences between the cholesterol levels before and after treatment.

μd = cholesterol level before treatment minus cholesterol level after treatment.

Before After difference

283 215 68

299 206 93

274 187 87

284 212 72

248 178 70

275 212 63

293 192 101

277 196 81

Sample mean, xd

= (68 + 93 + 87 + 72 + 70 + 63 + 101 + 81)/8 = 79.4

xd = 79.4

Standard deviation = √(summation(x - mean)²/n

n = 8

Summation(x - mean)² = (68 - 79.4)^2 + (93 - 79.4)^2 + (87 - 79.4)^2 + (72 - 79.4)^2 + (70 - 79.4)^2 + (63 - 79.4)^2 + (101 - 79.4)^2 + (81 - 79.4)^2 = 1253.88

Standard deviation = √(1253.88/8)

sd = 12.52

For the null hypothesis

H0: μd ≥ 0

For the alternative hypothesis

H1: μd < 0

This is a one tailed test(left tailed test)

The distribution is a students t. Therefore, degree of freedom, df = n - 1 = 8 - 1 = 7

The formula for determining the test statistic is

t = (xd - μd)/(sd/√n)

t = (79.4 - 0)/(12.52/√8)

t = 17.94

We would determine the probability value by using the t test calculator.

p < 0.00001

4) Assume alpha = 0.05

Since alpha, 0.05 > than the p value, then we would reject the null hypothesis. Therefore, at 5% level of significance, we cannot conclude that the mean cholesterol level after treatment is less than the mean before treatment.

6 0

3 years ago

Solve the system using elimination.

yan [13]

Answer:

y=-3

Step-by-step explanation:

5x+7y=-31

(-) 5x-9y+17

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

16y=-48

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

16 16

y=-3

8 0

2 years ago

2. You plant 48 seeds of a certain flower and 32 of them sprout. Find the

Neko [114]

Answer:

<em>The probability that the next flower seed will sprout is 0.667 or 66.7%</em>

Step-by-step explanation:

<u>Probability</u>

The experimental or empirical probability can be defined as the ratio of the number of times an event occurs to the total number of times the random activity was performed.

It can be calculated as the relative frequency of an event A in a sample space. The question states 32 seeds of a certain flower sprout out of 48 planted seeds. The relative frequency of success is computed as

$\displaystyle P(A)=\frac{32}{48}=\frac{2}{3}=0.667$

Thus, the probability that the next flower seed will sprout is 0.667 or 66.7%

6 0

3 years ago