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Sophie [7]
3 years ago
8

Solve equation by completing the square round to the nearest hundredth if necessary X2-4x-=5

Mathematics
1 answer:
kipiarov [429]3 years ago
6 0

Answer:

x=-1 and x=5

Step-by-step explanation:

we have

x^{2} -4x=5

Solve it by completing the square method

We take the coefficient of x that is -4, divide it by 2 and then square it

so

-\frac{4}{2}=-2

square it

(-2)^2 = 4

Adds 4 both sides

x^{2} -4x+4=5+4

Combine like terms right side

x^{2} -4x+4=9

Rewrite as perfect squares

(x-2)^{2}=9

take square root both sides

x-2=\pm3

x=2\pm3

therefore

x=2+3=5

x=2-3=-1

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Can help me complete this problem please :c
FrozenT [24]

Answer:

112.5 deg

Step-by-step explanation:

First we find the area of the entire circle.

A = pi * r^2

A = pi * (4 m)^2

A = 16pi m^2

The entire circle has area = 16pi m^2.

The sector has area 5pi m^2.

Now we find the fraction the area of the sector is of the entire circle.

fraction = (5pi m^2)/(16pi m^2) = 5/16 = 0.3125

The full circle has a central angle of 360 deg, the entire circle.

The measure of the central angle of the arc of the sector is the same fraction of the entire circle.

measure of sector angle = 0.3125 * 360 deg = 112.5 deg

4 0
3 years ago
Read 2 more answers
A doctor is measuring the mean systolic blood pressure of female students at a large college. Systolic blood pressure is known t
Nana76 [90]

Answer:

The correct option is (b).

Step-by-step explanation:

The (1 - <em>α</em>)% confidence interval for population mean (<em>μ</em>) is:

CI=\bar x\pm z_{\alpha/2}\times\frac{SD}{\sqrt{n}}

The confidence interval for population mean can be computed using either the <em>z</em>-interval or <em>t</em>-interval.

The <em>t</em>-interval is used if the following conditions are satisfied:

  • The population standard deviation is not known
  • The sample size is large enough
  • The population from which the sample is selected is normally distributed.

For computing a (1 - <em>α</em>)% confidence interval for population mean , it is necessary for the population to normally distributed if the sample selected is small, i.e.<em>n</em> < 30, because only then the sampling distribution of sample mean will be approximated by the normal distribution.

In this case the sample size is, <em>n</em> = 28 < 30.

Also it is provided that the systolic blood pressure is known to have a skewed distribution.

Since the sample is small and the population is not normally distributed, the  sampling distribution of sample mean will not be approximated by the normal distribution.

Thus, no conclusion can be drawn from the 90% confidence interval for the mean systolic blood pressure.

The correct option is (b).

5 0
3 years ago
Kerri said that the product of 3.93 and 0.07 would be about 4 and would have two decimal places. Is she correct?
oee [108]

Answer:

No.

Step-by-step explanation:

This type of problem is actually a trick problem. The question indicates that the PRODUCT of 3.93 and 0.07 would be about 4. The question is referring to the answer of the two values Multiplied to each other.

To visualize the question, we have:

3.93 x 0.07

This would give us:

0.2751

Kerri would be correct if she was looking for the SUM of the two values.

This would be:

3.93 + 0.07

This would give us:

4

Therefore in trick problems like this ones, it is better to look at what exactly is being asked.

8 0
4 years ago
Read 2 more answers
Maria took a math test last week. The table shows how many questions she answered correctly and incorrectly.
pashok25 [27]

Answer:

Step-by-step explanation:

Maria had a test with 20 questions

if 17 are correct,

20 questions................................100%

17 questions................................?%

she was 85% right

5 0
3 years ago
Solve 3x + 5 ⩾ x + 17
Ugo [173]

Answer:

Step-by-step explanation:

Simplifying

3x + 5 = x + 17

Reorder the terms:

5 + 3x = x + 17

Reorder the terms:

5 + 3x = 17 + x

Solving

5 + 3x = 17 + x

Solving for variable 'x'.

Move all terms containing x to the left, all other terms to the right.

Add '-1x' to each side of the equation.

5 + 3x + -1x = 17 + x + -1x

Combine like terms: 3x + -1x = 2x

5 + 2x = 17 + x + -1x

Combine like terms: x + -1x = 0

5 + 2x = 17 + 0

5 + 2x = 17

Add '-5' to each side of the equation.

5 + -5 + 2x = 17 + -5

Combine like terms: 5 + -5 = 0

0 + 2x = 17 + -5

2x = 17 + -5

Combine like terms: 17 + -5 = 12

2x = 12

Divide each side by '2'.

x = 6

Simplifying

x = 6

5 0
3 years ago
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