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3 years ago

Students at a middle school are divided into 6th, 7th, and 8th grades. A random sample of 15 students from each grade is chosen.

Mathematics

1 answer:

Julli [10]3 years ago

4 0

Answer:

B. Stratified random sample is the correct answer

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3 years ago

A letter is chosen from the word shown.

lakkis [162]

Answer:

That something unexpected is about to happen.

Step-by-step explanation:

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3 years ago

Solve the inequality 3(x+2)>0

Goryan [66]

Distribute
3x+6>0

Subtract 6 from both sides
3x>-6

Divide both sides by 3
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Final answer: x>-2

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4 years ago

What is the Quadratic Equation for these three points- <br>(1,3) (3,5) (5,7)

zlopas [31]

The required equation is y = x + 2

<u>Solution:</u>

Given three points are (1,3) (3,5) (5,7)

A quadratic equation for three points is given by $y = ax^2 + bx + c \rightarrow (1)$

Assume the point 1,3 and substitute in (1)

$\Rightarrow 3= a + b + c \rightarrow (2)$

Let us substitute 3,5 in (1)

$\Rightarrow 5 = 9a + 3b + c \rightarrow (3)$

Let us substitute 5,7 in (1)

$\Rightarrow 7 = 25a + 5b + c \rightarrow (4)$

Subtracting 2 and 3

$\Rightarrow 9a + 3b + c = 5 - ( a+ b+ c = 3)$

$\Rightarrow 8a + 2b = 2$

$\Rightarrow 4a + b = 1$

$\Rightarrow b = 1-4a$

Subtracting 4 and 3

$\Rightarrow 25a + 5b + c = 7 - ( 9a + 3b + c = 5)$

$\Rightarrow 16a + 2b = 2 \rightarrow (5)$

Substituting b in 5, $16a + 2(1 -4a) = 2$

$\Rightarrow 8a = 0$

$\Rightarrow a = 0; \ b = 1- 4(0) = 1$

$\Rightarrow b = 1 \\\\From \ 2, a + b + c =3$

$\Rightarrow 0+1+c =3$

$\Rightarrow c = 2$

Substituting a, b, c in 1 we get the quadratic equation $y = x + 2$

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3 years ago

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Step-by-step explanation:

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3 years ago