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2 years ago

PLEASE HELP ME OUT PLEASE AND I WILL GIVE BRAINLIES!!!!!!

Mathematics

1 answer:

vodka [1.7K]2 years ago

3 0

that is so easy your answer is 21

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Evaluate the expression when a=

Olin [163]

Answer:

$\frac{2}{15}$

Step-by-step explanation:

Substitute the values for a and c into the expression

- 2c + a

= - 2× $\frac{3}{10}$ + $\frac{11}{15}$

= - $\frac{3}{5}$ + $\frac{11}{15}$

= - $\frac{3(3)}{5(3)}$ + $\frac{11}{15}$

= - $\frac{9}{15}$ + $\frac{11}{15}$

= $\frac{2}{15}$

3 0

3 years ago

I need help please.

IgorLugansk [536]

Answer:

13 - 17 $\sqrt{11}$

Step-by-step explanation:

Using the rule

$\sqrt{a}$ × $\sqrt{a}$ = a

Each term in the second factor is multiplied by each term in the first factor, that is

2 $\sqrt{11}$ ( $\sqrt{11}$ - 9 ) + 1 ( $\sqrt{11}$ - 9 )

Distribute both parenthesis

= (2 × 11) - 18 $\sqrt{11}$ + $\sqrt{11}$ - 9

= 22 - 17 $\sqrt{11}$ - 9

= 13 - 17 $\sqrt{11}$

7 0

3 years ago

1) Solve the system by elimination?

lesya692 [45]

Answer:

1) (-6,-9)

times the top equation buy -4 so you cancel out the y

so it be -8x+4y=12 no cancel out the y's

so it be -8x=12 and 5x=6

now combined like terms to get -3x= 36

x = -6 now go plug that back in one of the equations to get y

y = -9

2) (-2,-5)

now on this one you going to substitute y= (2x-1) for y in the otheir eqaution

so it look like 3x-(2x-1)=-1

do your combining of like terms and your division & you get x = -2

now plug x in to y=2x-1 to get y = -5

6 0

3 years ago

A rectangular board is 1.8 meters long and 1.25 meters wide. What is the area of the board in square millimeters? Do not round y

lilavasa [31]

Answer:

2250000 mm^2 or 2.25 m^2

Step-by-step explanation:

Area=1.8*1.25=2.25 m^2=2250000 mm^2

7 0

3 years ago

A survey report states that 70% of adult women visit their doctors for a physical examination at least once in two years. If 20

irakobra [83]

Answer:

a) 0.3921 = 39.21% probability that fewer than 14 of them have had a physical examination in the past two years.

b) 0.107 = 10.7% probability that at least 17 of them have had a physical examination in the past two years.

Step-by-step explanation:

For each women, there are only two possible outcomes. Either they visit their doctors for a physical examination at least once in two years, or they do not. The probability of a woman visiting their doctor at least once in this period is independent of any other women. This means that we use the binomial probability distribution to solve this question.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

In which $C_{n,x}$ is the number of different combinations of x objects from a set of n elements, given by the following formula.

$C_{n,x} = \frac{n!}{x!(n-x)!}$

And p is the probability of X happening.

70% of adult women visit their doctors for a physical examination at least once in two years.

This means that $p = 0.7$

20 adult women

This means that $n = 20$

(a) Fewer than 14 of them have had a physical examination in the past two years.

This is:

$P(X < 14) = 1 - P(X \geq 14)$

In which

$P(X \geq 14) = P(X = 14) + P(X = 15) + P(X = 16) + P(X = 17) + P(X = 18) + P(X = 19) + P(X = 20)$

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 14) = C_{20,14}.(0.7)^{14}.(0.3)^{6} = 0.1916$

$P(X = 15) = C_{20,15}.(0.7)^{15}.(0.3)^{5} = 0.1789$

$P(X = 16) = C_{20,16}.(0.7)^{16}.(0.3)^{4} = 0.1304$

$P(X = 17) = C_{20,14}.(0.7)^{17}.(0.3)^{3} = 0.0716$

$P(X = 18) = C_{20,18}.(0.7)^{18}.(0.3)^{2} = 0.0278$

$P(X = 19) = C_{20,19}.(0.7)^{19}.(0.3)^{1} = 0.0068$

$P(X = 20) = C_{20,20}.(0.7)^{20}.(0.3)^{0} = 0.0008$

$P(X \geq 14) = P(X = 14) + P(X = 15) + P(X = 16) + P(X = 17) + P(X = 18) + P(X = 19) + P(X = 20) = 0.1916 + 0.1789 + 0.1304 + 0.0716 + 0.0278 + 0.0068 + 0.0008 = 0.6079$

$P(X < 14) = 1 - P(X \geq 14) = 1 - 0.6079 = 0.3921$

0.3921 = 39.21% probability that fewer than 14 of them have had a physical examination in the past two years.

(b) At least 17 of them have had a physical examination in the past two years

$P(X \geq 17) = P(X = 17) + P(X = 18) + P(X = 19) + P(X = 20)$

From the values found in item (a).

$P(X \geq 17) = P(X = 17) + P(X = 18) + P(X = 19) + P(X = 20) = 0.0716 + 0.0278 + 0.0068 + 0.0008 = 0.107$

0.107 = 10.7% probability that at least 17 of them have had a physical examination in the past two years.

6 0

3 years ago