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3 years ago

Graphing inequalities

1 answer:

8 0

There are three steps:
1.)Rearrange the equation so "y" is on the left and everything else on the right.

2.)Plot the "y=" line (make it a solid line for y≤ or y≥, and a dashed line for y< or y>)

3.)Shade above the line for a "greater than" (y> or y≥) or below the line for a "less than" (y< or y≤).

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4trig review please help me

egoroff_w [7]

Answer:

$4 \sqrt{3}$

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3 years ago

A population has a mean of 400 and a standard deviation of 90. suppose a sample of size 100 is selected and x is used to estimat

Over [174]

What were your given answer choices

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3 years ago

Which would be the best method to use to solve the following equations? Explain your reasoning.

o-na [289]

A. square root property

$3x^2-192=0\\x^2-66=0\\x^2=66\\x= -\sqrt{66} or \sqrt{66}$

it has one value with x which is x^2 and it cn be easily solved without having to factorise, quadratic formula cant be used as it need ax^2+bx+c=0 format

B. factorising

$x^2-x-6=0\\x^2+2x-3x-6=0\\(x+2)(x-3)=0\\x+2=0 and x-3=0\\x= -2 \\x= 3$

i just felt like this was easier to factorise than the other 2 options left

C. Completing the square

$x^2-6x-7=0\\(x-3)^2=0\\x= -1\\x= 7$

same reason personal preference

D- Quadratic

$x^2-17x-7=0\\x=\frac{-(-17)+\sqrt{(-17)^2-4(1)(-7)} }{2(1)} \\x=\frac{-(-17)-\sqrt{(-17)^2-4(1)(-7)} }{2(1)}\\x=17.4\\x=-0.402$

the 17 kinda threw me off and i didnt wanna get on factorising or doing completing the square so quadratic formal

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2 years ago

Hewooooooo •ᴗ• ~~~~~~~~

const2013 [10]

Answer:

hi hru

Step-by-step explanation:

7 0

3 years ago

Read 2 more answers

The Weschler Intelligence Scale for Children (WISC) is an intelligence test designed for children between the ages of 6 and 16.

Ostrovityanka [42]

Answer:

a) $\bar X = 121.4$

b) $SE = \frac{\sigma}{\sqrt{n}}= \frac{15}{\sqrt{40}}=2.372$

c) $121.4-1.64\frac{15}{\sqrt{40}}=117.51$

$121.4+1.64\frac{15}{\sqrt{40}}=125.29$

Step-by-step explanation:

Data given: 126,111,141,96,123,115,116,113,127,114,122,116,104,126,126,132,139,111,143,121,119,107,154,125,120,135,142,132,94,103,143,115,132,107,118,105,101,135,94,153

Part a

For this case we can calculate the sample mean with the following formula:

$\bar X = \frac{\sum_{i=1}^n X_i}{n}$

And after replace we got:

$\bar X = 121.4$

Part b

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

For this case we assume that the population deviation is $\sigma=15$ , we can calculate the standard error with this formula:

$SE = \frac{\sigma}{\sqrt{n}}= \frac{15}{\sqrt{40}}=2.372$

Part c

The confidence interval for the mean is given by the following formula:

$\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (1)

Since the Confidence is 0.90 or 90%, the value of $\alpha=0.1$ and $\alpha/2 =0.05$ , and we can use excel, a calculator or a tabel to find the critical value. The excel command would be: "=-NORM.INV(0.05,0,1)".And we see that $z_{\alpha/2}=1.64$

Now we have everything in order to replace into formula (1):

$121.4-1.64\frac{15}{\sqrt{40}}=117.51$

$121.4+1.64\frac{15}{\sqrt{40}}=125.29$

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3 years ago

Read 2 more answers