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adell [148]
3 years ago
9

Solve the system by the substitution method. x + y = 2 y= x2 - 6x + 8

Mathematics
1 answer:
ruslelena [56]3 years ago
8 0

Answer:

The solution of the given system is (2,0)

Step-by-step explanation:

Here, the given system of equations is:

x + y = 2    .............. (1)

y= x^2 - 6x +  8  ........  (2)

Now from (1) x = 2 - y

Substitute this value of x = 2- y in (2) ,we get:

y= (2-y)^2 - 6(2-y) +  8\\\implies y = 4 + y^2 - 4y - 12 + 6y + 8\\or, y^2 + y  = 0\\\implies y(y +1) = 0

⇒  y = 0 or,  y = -1

Now, if y = 0, x  = 2

and if x= -1, y = 2-(-1)  = 2+1  = 3, or y = 3

But (x = -1 , y = 3 )is NOT  a solution of (2).

Hence, the solution of the given system is (2,0)

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Suppose that birth weights are normally distributed with a mean of 3466 grams and a standard deviation of 546 grams. Babies weig
Anon25 [30]

Answer:

3.84% probability that it has a low birth weight

Step-by-step explanation:

Problems of normally distributed samples are solved using the z-score formula.

In a set with mean \mu and standard deviation \sigma, the zscore of a measure X is given by:

Z = \frac{X - \mu}{\sigma}

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

In this problem, we have that:

\mu = 3466, \sigma = 546

If we randomly select a baby, what is the probability that it has a low birth weight?

This is the pvalue of Z when X = 2500. So

Z = \frac{X - \mu}{\sigma}

Z = \frac{2500 - 3466}{546}

Z = -1.77

Z = -1.77 has a pvalue of 0.0384

3.84% probability that it has a low birth weight

3 0
3 years ago
The number of students at Lala High School is 64 less than 3 times the number of students at Banana High School. Which expressio
dangina [55]

Answer:

3s - 64

Step-by-step explanation:

7 0
3 years ago
Simplify by combining like terms. -4a + b + 9 + a -b-3 plz help !
Sedaia [141]

Answer:

- 3a + 6

Step-by-step explanation:

subtract and add like items together like

- 4a + a = -3a

b-b= 0

and

9-3 = 6

so the answer is

-3a +6

3 0
3 years ago
How to solve these question?
mart [117]
3.) An extreme value refers to a point on the graph that is possibly a maximum or minimum. At these points, the instantaneous rate of change (slope) of the  graph is 0 because the line tangent to the point is horizontal. We can find the rate of change  by taking the derivative of the function.

y' = 2ax + b

Now that we where the derivative, we can set it equal to 0.

2ax + b = 0

We also know that at the extreme value, x = -1/2. We can plug that in as well.

2a (-\frac{1}{2} ) + b = 0

The 2 and one-half cancel each other out.

-a + b = 0

a = b

Now we know that a and b are the same number, and that ax^2 + bx + 10 = 0 at x = -1/2. So let's plug -1/2 in for x in the original function, and solve for a/b.

a(-0.5)^2 + a(-0.5) + 10 = 0

0.25a - 0.5a + 10 = 0

-0.25a = -10

a = 40

b = 40

To determine if the extrema is a minima or maxima, we need to go back to the derivative and plug in a/b.

80x + 40

Our critical number is x = -1/2. We need to plug a number that is less than -1/2  and a number that is greater than -1/2 into the derivative.

LESS THAN:
80(-1) + 40 =  -40

GREATER THAN:
80(0) + 40 = 40

The rate of change of the graph changes from negative  to positive at x = -1/2, therefore the extreme value is a minimum.

4.) If the quadratic function is symmetrical about x = 3, that means that the minimum or maximum must be at x = 3.

y' = 2ax + 1

2a(3) + 1 = 0

6a = -1

a = -1/6

So now plug the a value and x=3 into the original function to find the extreme value.

(-1/6)(3)^2 + 3 + 3 = 4.5

The extreme value is 4.5


7 0
2 years ago
I need help like really bad.
Lelechka [254]

Answer:

PEMDAS

Step-by-step explanation:

parenthesis

Exponents

Multiply

Divide

Add

Subtract

6 0
2 years ago
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