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3 years ago

Which of the following is a solution of x^2 + 2x + 8?

Mathematics

1 answer:

denis-greek [22]3 years ago

4 0

X^2 + 2x + 8 = 0

(x + 1)^2 - 1 + 8 = 0

(x + 1)^2 = -7

x + 1 = sqrt (-7) = i sqrt7

x = -1 + i sqrt7

Its B

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15% of Alina’s workout consisted of cardio exercise. 25% of Dane’s workout consisted of cardio exercise. Which statement must be

Arisa [49]

The correct answer is B. If Alina’s workout was 80 minutes, and Dane’s workout was 48 minutes, they spent the same amount of time on cardio exercise.

To figure this out, first find 15% of 80 and then 25% of 48.

To find 15% of 80, you can first find 10% of 80 which is 8(just move the decimal one place to the left). The remaining 5% will be half of 8 since 8 is 10%. Add both the numbers up and you will get 12. (8+4=12)

To find 25% of 48, you can divide 48 by 4. Since percent means 'out of 100', 25% is 25 of 100. 100 divided by 25 is equal to 4. So, 48 divided by 4 is equal to 12.

So, the final answer is B. They both equal to 12.

Hope it helps :)

6 0

3 years ago

The following observations are on stopping distance (ft) of a particular truck at 20 mph under specified experi- mental conditio

zzz [600]

Answer:

see explaination

Step-by-step explanation:

Data : 32.1 , 30.6 , 31.4 , 30.4 , 31.0 , 31.9

Mean X-bar = 31.23

SD = 0.689

Null Hypothesis : Xbar = mu

Alternate Hypothesis : Xbar > mu

z = (Xbar - mu) / (SD/sqrt(n))

= (31.23 - 30 ) /(0.689/sqrt(6))

= 4.372

P-value = ~0

Since P-vale < 0.01 , we will reject null hypothesis.

The data suggest that true average stopping ditance exceeds the maximum.

i) SD = 0.65

mu = 31

z = (Xbar - mu) / (SD/sqrt(n))

= (31.23 - 31) /(0.65/sqrt(6))

= 0.867

P-value = 0.3859 Answer

ii) SD = 0.65

mu = 32

z = (Xbar - mu) / (SD/sqrt(n))

= (31.23 - 32) /(0.65/sqrt(6))

= -2.9

P-value = 0.0037 Answer

i) SD = 0.8

mu = 31

z = (Xbar - mu) / (SD/sqrt(n))

= (31.23 - 31) /(0.8/sqrt(6))

= 0.704

P-value = 0.4814 Answer

ii) SD = 0.8

mu = 32

z = (Xbar - mu) / (SD/sqrt(n))

= (31.23 - 32) /(0.8/sqrt(6))

= -2.357

P-value = 0.0184 Answer

The probabilities obtained in part c are comparatively higher than that of part b.

i) For alpha =0.01

z = (Xbar - mu) / (SD/sqrt(n))

=> -2.32 = (31.23 - 31) /(0.65/sqrt(n))

=> (0.65/sqrt(n)) = (31.23 - 31)/-2.32

=> sqrt(n) = (0.65*(-2.32)) / (31.23 - 31)

=> n = 43 Answer

ii) For beta =0.10

z = (Xbar - mu) / (SD/sqrt(n))

=> -1.28 = (31.23 - 31) /(0.65/sqrt(n))

=> (0.65/sqrt(n)) = (31.23 - 31)/-1.28

=> sqrt(n) = (0.65*(-1.28)) / (31.23 - 31)

=> n = 13 Answer

4 0

2 years ago

Construct a quadratic polynomial whose zeroes are negatives of the zeroes of the

sp2606 [1]

Given:

The given quadratic polynomial is :

$x^2-x-12$

To find:

The quadratic polynomial whose zeroes are negatives of the zeroes of the given polynomial.

Solution:

We have,

$x^2-x-12$

Equate the polynomial with 0 to find the zeroes.

$x^2-x-12=0$

Splitting the middle term, we get

$x^2-4x+3x-12=0$

$x(x-4)+3(x-4)=0$

$(x+3)(x-4)=0$

$x=-3,4$

The zeroes of the given polynomial are -3 and 4.

The zeroes of a quadratic polynomial are negatives of the zeroes of the given polynomial. So, the zeroes of the required polynomial are 3 and -4.

A quadratic polynomial is defined as:

$x^2-(\text{Sum of zeroes})x+\text{Product of zeroes}$

$x^2-(3+(-4))x+(3)(-4)$

$x^2-(-1)x+(-12)$

$x^2+x-12$

Therefore, the required polynomial is $x^2+x-12$ .

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3 years ago

The table on the right shows last initials of basketball players and the number of games played by each. Find the z-score for p

Umnica [9.8K]

The answer is J 73
a a

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3 years ago

What is the image of (-5, -1) after a reflection over the x-axis?

elena55 [62]

Answer:

(-5,1)

Step-by-step explanation:

solved by graphing

5 0

3 years ago

Read 2 more answers