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3 years ago

5

a normal distribution with a mean of 85 and a standard deviation of 12. What is the proportion between 80 and 90? u =85 s =12. P

(80

1 answer:

Neko [114]3 years ago

4 0

I think the answer is 44

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Find the student’s error in solving the following inequality.

Mars2501 [29]

Answer:

The correct option is:

The student should have switched the direction of the inequality sign to get –5> x for a final answer

Step-by-step explanation:

The students has made a mistake in the 3rd step.

We know that when we multiply or divide any negative number on both sides of the inequality, the sign of inequality reverse its direction.

In step 3 the student divided 25 by -5 but did not switch direction of the inequality sign.

Therefore the correct option is: The student should have switched the direction of the inequality sign to get –5> x for a final answer

5 0

3 years ago

The ANSWER is what I need to know.

tensa zangetsu [6.8K]

They both represent the expression, because when simplified the expression equals 8x+4, but you could also write it like 2(3x+2)+2x

8 0

3 years ago

Mark can type 20 words per minute. Carol can type 22 words per minute. Mark starts typing at 1:00 pm and Carol starts typing 6 m

Anna11 [10]

Answer:

C. 498

Step-by-step explanation:

8 0

3 years ago

Help with my algebra homework.

just olya [345]

Q1. The answer is $\frac{(x-4)(x-4)}{(x+3)(x+1)}= \frac{ x^{2}-4x-4x+16}{ x^{2} +x+3x+3} = \frac{ x^{2} -8x+16}{ x^{2} +4x+3}$
$\frac{ x^{2} -16}{ x^{2} +5x+6} / \frac{ x^{2} +5x+4}{ x^{2} -2x-8} = \frac{ x^{2} -16}{ x^{2} +5x+6}* \frac{x^{2} -2x-8}{ x^{2} +5x+4}$
Now, factorise the numerators and denominators:
x² - 16 = x² - 4² = (x + 4)(x - 4)
x² + 5x + 6 = x² + 2x + 3x + 2*3 = x(x+2) + 3(x+2) = (x + 2)(x + 3)
x² - 2x - 8 = x² + 2x - 4x - 2*4 = x(x+2) - 4(x+2) = (x + 2)(x - 4)
x² + 5x + 4 = x² + x + 4x + 4*1 = x(x+1) + 4(x+1) = (x + 1)(x + 4)

$\frac{ x^{2} -16}{ x^{2} +5x+6}* \frac{x^{2} -2x-8}{ x^{2} +5x+4}= \frac{(x+4)(x-4)}{(x+2)(x+3)} * \frac{(x+2)(x-4)}{(x+1)(x+4)}$
Now, cancel out some factors:
$\frac{(x+4)(x-4)}{(x+2)(x+3)} * \frac{(x+2)(x-4)}{(x+1)(x+4)}= \frac{(x-4)(x-4)}{(x+3)(x+1)}= \frac{ x^{2}-4x-4x+16}{ x^{2} +x+3x+3} = \frac{ x^{2} -8x+16}{ x^{2} +4x+3}$

Q2. The answer is $\frac{7(a-7)}{(a-8)(a+8)}$
Since a² - b² = (a-b)(a+b), then a²- 64 = a² - 8² = (a-8)(a+8).
$\frac{7}{a+8} + \frac{7}{ a^{2} -64} = \frac{7}{a+8} + \frac{7}{ (a+8)(a-8)}= \frac{7(a-8)}{(a+8)(a-8)} + \frac{7}{ (a+8)(a-8)}= \frac{7(a-8)+7}{ (a+8)(a-8)}$
$= \frac{7(a-8)+7*1}{(a+8)(a-8)} =\frac{7(a-8+1)}{(a+8)(a-8)} =\frac{7(a-7)}{(a+8)(a-8)}$

Q3. The answer is $\frac{7(3a-4)}{(a-6)(a+8)}$
$\frac{ a^{2} -2a-3}{ a^{2}-9a+18 }- \frac{a^{2} -5a-6}{ a^{2}+9a+8 } = \frac{a^{2}+a-3a-3*1}{a^{2}-3a-6a+3*6} - \frac{a^{2}-a-6a-6*1}{a^{2}+a+8a+8*1}$
$= \frac{a(a+1)-3(a+1)}{a(a-3)-6(a-3)}- \frac{a(a+1)-6(a+1)}{a(a+1)+8(a+1)}= \frac{(a+1)(a-3)}{(a-6)(a-3)} - \frac{(a+1)(a-6)}{(a+1)(a+8)}$
Now, cancel out some factors:
$\frac{(a+1)(a-3)}{(a-6)(a-3)} - \frac{(a+1)(a-6)}{(a+1)(a+8)}= \frac{a+1}{a-6} - \frac{a-6}{a+8}$
$\frac{a+1}{a-6} - \frac{a-6}{a+8}= \frac{(a+1)(a+8)}{(a-6)(a+8)} -\frac{(a-6)(a-6)}{(a-6)(a+8)} =\frac{(a+1)(a+8)-(a-6)(a-6)}{(a-6)(a+8)}$
$= \frac{ a^{2} +9a+8- a^{2} +12-36}{(a-6)(a+8)} =\frac{9a+8+12-36}{(a-6)(a+8)} =\frac{21a-28}{(a-6)(a+8)} =\frac{7(3a-4)}{(a-6)(a+8)}$

Q4. The answer is $\frac{4x}{(x+3)(1+3x)}=\frac{4x}{ x^{2} +10x+3}$
$\frac{4}{x+3} / (\frac{1}{x}+3 )=\frac{4}{x+3} / (\frac{1}{x}+ \frac{3x}{x})=\frac{4}{x+3} / (\frac{1+3x}{x})= \frac{4}{x+3} * \frac{x}{1+3x} = \frac{4x}{(x+3)(1+3x)}$
$\frac{4x}{(x+3)(1+3x)}= \frac{4x}{x+3 x^{2} +3+9x}= \frac{4x}{ x^{2} +10x+3}$

Q5. The answer is x = 6
$\frac{-2}{x} +4= \frac{4}{x} +3$
$4-3= \frac{4}{x}- \frac{-2}{x}$
$1 = \frac{4-(-2)}{x}$
$1= \frac{4+2}{x}$
$1= \frac{6}{x}$
$x = 6$
Let's check the solution:
Since: $\frac{-2}{x} +4= \frac{4}{x} +3$
Then: $\frac{-2}{6}+4 = \frac{4}{6} +3$
$- \frac{1}{3}+ \frac{4*3}{3}= \frac{2}{3} + \frac{3*3}{3}$
$- \frac{1}{3} + \frac{12}{3} = \frac{2}{3} + \frac{9}{3}$
$\frac{-1+12}{3} = \frac{2+9}{3}$
$\frac{11}{3} = \frac{11}{3}$
Thus, the solution is correct

6 0

3 years ago

Answer the other following question.

pychu [463]

Given:

L = W - 4

P = 2L + 2W

We can substitute 2L for 2(W - 4) = 2W - 8

So:

2W - 8 + 2W = P

P = 4W - 8

Answer is 4. 4W-8

5 0

3 years ago