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3 years ago

18. Solve x^2+ 6x - 16 = 0 by completing the square. Please give detailed steps!!

Mathematics

1 answer:

MakcuM [25]3 years ago

4 0

Answer:

x1 = -8, x2= 2

Step-by-step explanation:

1. Write 6x as a difference

= x^2 + 8x - 2x - 16 = 0

2. Factor the expressions

= x ( x + 8 ) - 2x - 16 = 0

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

Factor out x + 8 from the expression

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

3. When the product of factors = 0, at least one factor is 0

x + 8 = 0

x - 2 = 0

4. Solve the equation for x

x = - 8

x = 2

Therefore, the equation has 2 solutions :

x1 = -8, x2 = 2

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Qué expresión es igual a 6(-3m)

jeka94

6(-3m) = 6 x (-3)m,

6 x -3 = -18

-18m is your answer

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4 years ago

n a survey of a group of men, the heights in the 20-29 age group were normally distributed, with a mean of inches and a stand

kotykmax [81]

Answer:

(a) The probability that a study participant has a height that is less than 67 inches is 0.4013.

(b) The probability that a study participant has a height that is between 67 and 71 inches is 0.5586.

(c) The probability that a study participant has a height that is more than 71 inches is 0.0401.

(d) The event in part (c) is an unusual event.

Step-by-step explanation:

The complete question is: In a survey of a group of men, the heights in the 20-29 age group were normally distributed, with a mean of 67.5 inches and a standard deviation of 2.0 inches. A study participant is randomly selected. Complete parts (a) through (d) below. (a) Find the probability that a study participant has a height that is less than 67 inches. The probability that the study participant selected at random is less than inches tall is nothing. (Round to four decimal places as needed.) (b) Find the probability that a study participant has a height that is between 67 and 71 inches. The probability that the study participant selected at random is between and inches tall is nothing. (Round to four decimal places as needed.) (c) Find the probability that a study participant has a height that is more than 71 inches. The probability that the study participant selected at random is more than inches tall is nothing. (Round to four decimal places as needed.) (d) Identify any unusual events. Explain your reasoning. Choose the correct answer below.

We are given that the heights in the 20-29 age group were normally distributed, with a mean of 67.5 inches and a standard deviation of 2.0 inches.

Let X = the heights of men in the 20-29 age group

The z-score probability distribution for the normal distribution is given by;

Z = $\frac{X-\mu}{\sigma}$ ~ N(0,1)

where, $\mu$ = population mean height = 67.5 inches

$\sigma$ = standard deviation = 2 inches

So, X ~ Normal( $\mu=67.5, \sigma^{2}=2^{2}$ )

(a) The probability that a study participant has a height that is less than 67 inches is given by = P(X < 67 inches)

P(X < 67 inches) = P( $\frac{X-\mu}{\sigma}$ < $\frac{67-67.5}{2}$ ) = P(Z < -0.25) = 1 - P(Z $\leq$ 0.25)

= 1 - 0.5987 = 0.4013

The above probability is calculated by looking at the value of x = 0.25 in the z table which has an area of 0.5987.

(b) The probability that a study participant has a height that is between 67 and 71 inches is given by = P(67 inches < X < 71 inches)

P(67 inches < X < 71 inches) = P(X < 71 inches) - P(X $\leq$ 67 inches)

P(X < 71 inches) = P( $\frac{X-\mu}{\sigma}$ < $\frac{71-67.5}{2}$ ) = P(Z < 1.75) = 0.9599

P(X $\leq$ 67 inches) = P( $\frac{X-\mu}{\sigma}$ $\leq$ $\frac{67-67.5}{2}$ ) = P(Z $\leq$ -0.25) = 1 - P(Z < 0.25)

= 1 - 0.5987 = 0.4013

The above probability is calculated by looking at the value of x = 1.75 and x = 0.25 in the z table which has an area of 0.9599 and 0.5987 respectively.

Therefore, P(67 inches < X < 71 inches) = 0.9599 - 0.4013 = 0.5586.

(c) The probability that a study participant has a height that is more than 71 inches is given by = P(X > 71 inches)

P(X > 71 inches) = P( $\frac{X-\mu}{\sigma}$ > $\frac{71-67.5}{2}$ ) = P(Z > 1.75) = 1 - P(Z $\leq$ 1.75)

= 1 - 0.9599 = 0.0401

The above probability is calculated by looking at the value of x = 1.75 in the z table which has an area of 0.9599.

(d) The event in part (c) is an unusual event because the probability that a study participant has a height that is more than 71 inches is less than 0.05.

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3 years ago

A rancher has a 3-sided plot of land that will be used for grazing sheep. Each side length is a multiple of 100. One side is 300

telo118 [61]

Answer:

yes

Step-by-step explanation:

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3 years ago

N is an integer such that 3n + 4 < 19 and

Alekssandra [29.7K]

Answer:

Step-by-step explanation:

3n+4<19

3n<19-4

3n<15

n<5

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combining

(-∞,-16)U(16/9,5)

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3 years ago

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Jordan was successful in 10 out of 15 foul shots. what is the percent of the shots that he was successful?

svetlana [45]

17.3% is the percentage of shots he was successful with.

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3 years ago

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