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4 years ago

Solve systems of equations -x^2-4x+y=0 -x^2+9x+y+13=0

Mathematics

1 answer:

Ksju [112]4 years ago

7 0

Answer:

I solve it by substitution

y=x^2+4x

-x^2+9x+(x^2+4x)+13=0

13x+13=0

13x=-13

x= -13/13

x= -1

y=x^2+4x=1-4

y= -3

Step-by-step explanation:

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Which graph best represents the equation x2 + (y – 1)2 = 3?

Harman [31]

Answer:

Step-by-step explanation:

assuming the equation is x^2 + (y - 1)^2 = 3

6 0

2 years ago

It is known that 50% of adult workers have a high school diploma. If a random sample of 8 adult workers is selected, what is the

son4ous [18]

Answer:

85.56% probability that less than 6 of them have a high school diploma

Step-by-step explanation:

For each adult, there are only two possible outcomes. Either they have a high school diploma, or they do not. The probability of an adult having a high school diploma is independent of other adults. So 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.

50% of adult workers have a high school diploma.

This means that $p = 0.5$

If a random sample of 8 adult workers is selected, what is the probability that less than 6 of them have a high school diploma

This is P(X < 6) when n = 8.

$P(X < 6) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4) + P(X = 5)$

In which

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

$P(X = 0) = C_{8,0}.(0.5)^{0}.(0.5)^{8} = 0.0039$

$P(X = 1) = C_{8,1}.(0.5)^{1}.(0.5)^{7} = 0.0313$

$P(X = 2) = C_{8,2}.(0.5)^{2}.(0.5)^{6} = 0.1094$

$P(X = 3) = C_{8,3}.(0.5)^{3}.(0.5)^{5} = 0.2188$

$P(X = 4) = C_{8,4}.(0.5)^{4}.(0.5)^{4} = 0.2734$

$P(X = 5) = C_{8,5}.(0.5)^{5}.(0.5)^{3} = 0.2188$

$P(X < 6) = P(X = 0) + P(X = 1) + P(X = 2) + P(X = 3) + P(X = 4) + P(X = 5) = 0.0039 + 0.0313 + 0.1094 + 0.2188 + 0.2734 + 0.2188 = 0.8556$

85.56% probability that less than 6 of them have a high school diploma

7 0

3 years ago

Use a system of equations to solve this problem. Dr. Graham currently has two acid solutions. She only has a 60% acid solution a

Natalka [10]

<span>Dr. Graham currently has two acid solutions.
60% acid AND 20% acid </span>
Dr. Graham needs 30 L of a 50% acid solution
We set up 2 equations in which s = 60% acid and t = 20% acid
A) s + t = 30
B) .60s + .20t = (.50 * 30)
We multiply equation A by -.20
A) = -.20s -.20t = -6 then we add it to B)
B) .60s + .20t = 15
.40s = 9
s = 22.5
t = 7.5
So, she needs to mix 22.5 liters of 60% acid with 7.5 liters of 20% acid.

Source:
http://1728.org/mixture.htm

4 0

3 years ago

Can measurement 6cm, 8cm, and 14 cm create a triangle

stira [4]

Answer:

Step-by-step explanation:

6 0

3 years ago

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What is the area of the triangle?

garri49 [273]

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