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2 years ago

What is 4x(5x-2)=20x-2

Mathematics

1 answer:

Zanzabum2 years ago

7 0

Answer: x = 1.32 and x= 0.076

Step-by-step explanation:

4x(5x-2) = 20x-2

20x^2-8x = 20x-2

20x^2-8x-20x+2=0

20x^2-28x+2=0

Using quadratic equation

x = (-b +or- √(b^2-4ac))/2a

a =20, b=28, c= 2

Substitute into the equation

x= (7+√39)/10. = 1.32

x = (7-√39)/10 = 0.076

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Anyone know the answer I’m lost…

Artist 52 [7]

Answer:

#1: -1

#2: 1

Step-by-step explanation:

Anything raised to the 0 power is 1, but in question 1 the negative is outside the parenthesis, so it makes it -1.

5 0

2 years ago

Calculate the sample standard deviation and sample variance for the following frequency distribution of hourly wages for a sampl

lidiya [134]

Answer:

(a) The sample variance is 16.51

(a) The sample standard deviation is 4.06

Step-by-step explanation:

Given

$\begin{array}{cc}{Class} & {Frequency} & 8.26 - 10.00 & 20 &10.01-11.75 & 38 &11.76 - 13.50& 36 & 13.51-15.25 &25&15.26-17.00 &27 &\ \end{array}$

Solving (a); The sample variance.

First, calculate the class midpoints.

This is the mean of the intervals.

i.e.

$x_1 = \frac{8.26+10.00}{2} = \frac{18.26}{2} = 9.13$

$x_2 = \frac{10.01+11.75}{2} = \frac{21.76}{2} = 10.88$

$x_3 = \frac{11.76+13.50}{2} = \frac{25.26}{2} = 12.63$

$x_4 = \frac{13.51+15.25}{2} = \frac{28.76}{2} = 14.38$

$x_5 = \frac{15.26+17.00}{2} = \frac{32.26}{2} = 16.13$

So, the table becomes:

$\begin{array}{ccc}{Class} & {Frequency} & {x} & 8.26 - 10.00 & 20&9.13 &10.01-11.75 & 38 &10.88&11.76 - 13.50& 36 &12.63& 13.51-15.25 &25&14.38&15.26-17.00 &27 &16.13\ \end{array}$

Next, calculate the mean

$\bar x = \frac{\sum fx}{\sum f}$

$\bar x = \frac{20*9.13 + 38 * 10.88+36*12.63+25*14.38+27*16.13}{20+38+36+25+27}$

$\bar x = \frac{1845.73}{146}$

$\bar x = 12.64$

Next, the sample variance is:

$\sigma^2 = \frac{\sum f(x - \bar x)^2}{\sum f - 1}$

So, we have:

$\sigma^2 = \frac{20*(9.13-12.63)^2 + 38 * (10.88-12.63)^2 +...........+27 * (16.13 -12.63)^2}{20+38+36+25+27-1}$

$\sigma^2 = \frac{2393.6875}{145}$

$\sigma^2 = 16.51$

The sample standard deviation is:

$\sigma = \sqrt{\sigma^2}$

$\sigma = \sqrt{16.51}$

$\sigma = 4.06$

6 0

2 years ago

Simplify, and list any restrictions on the variable: (2x(x-4)/(4x^2-64)

uysha [10]

Answer:

WHEN SIMPLIFIED THE ANSWER WILL BE:

Step-by-step explanation:

(X)/(2(X+4)

8 0

3 years ago

A landscape plan includes a rectangular flowers bed that is surrounded the wood in planks. In the drawing, the rectangular flowe

forsale [732]

Answer:

The perimeter of the drawing: 18 inches

The perimeter of the actual flower bed: 540 inches

If they were multiplied by 24 instead the actual perimeter of the flower bed would be 432 inches. The effect is that it decreases by 108 inches.

Step-by-step explanation:

Taking the 4 inches and 5 inches and multiplying them by 30 gets 120 by 150. If its a rectangle we will add together all 4 sides to get the perimeter of the actual one.

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2 years ago

Two-thirds of the difference between a number and four is six

hodyreva [135]

2/3 times x-4 = 6
thats the answer :)

7 0

3 years ago