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3 years ago

What is the sum of 5(−3.4k−7) (3k 21) =

1 answer:

8 0

I am assuming that the correct equation is 5(-3.4k - 7) + (3k 21) to get the sum.

distribute multiplication:

5(-3.4k) - 5(7) + (3k*21) = 0
-17k - 35 + 63k = 0

Look for k:

-17k + 63k = 35
46k = 35
46k / 46 = 35 / 46
k = 0.76

Substitute k with 0.76

5(-3.4k - 7) + (3k21) = 0
5[(-3.4)(0.76) - 7] + [{(3)(0.76)}21] = 0
5(-2.584 - 7) + (2.28)(21) = 0
5(-2.584) - 5(7) + 47.88 = 0
-12.92 - 35 + 47.88 = 0
- 47.92 + 47.88 = 0.04

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Step-by-step explanation:

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2 years ago

You have D dollars to buy fence to enclose a rectangular plot of land (see figure at right). The fence for the top and bottom co

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The perimeter of the rectangular plot of land is given by the expression below

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Furthermore, the area of the enclosed land is given by

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Substituting into the equation for the area,

$\begin{gathered} A=(\frac{D-6y}{8})y \\ \Rightarrow A=\frac{D}{8}y-\frac{3}{4}y^2 \end{gathered}$

To find the maximum possible area, solve A'(y)=0, as shown below

$\begin{gathered} A^{\prime}(y)=0 \\ \Rightarrow\frac{D}{8}-\frac{3}{2}y=0 \\ \Rightarrow\frac{3}{2}y=\frac{D}{8} \\ \Rightarrow y=\frac{D}{12} \end{gathered}$

Therefore, the corresponding value of x is

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1 year ago

The volume of the cube below is 250.047 m^3. The side length could be between which sets of numbers below?

Eva8 [605]

Step-by-step explanation:

The volume of the cube below is 250.047 m^3. The side length could be between which sets of numbers below?

A. 4 cm and 5cm

B 5cm and 6 cm

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ans.C

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2 years ago

Micah rows his boat on a river 4.48 miles downstream, with the current, in 0.32 hours. He rows back upstream the same distance,

denpristay [2]

Let the speed of the current be y and the speed of Micah's sailing speed be x. Then 4.48/(x + y) = 0.32
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0.32x + 0.32y = 4.48 . . . (1)
0.56x - 0.56y = 4.48 . . . (2)
(1) x 7 => 2.24x + 2.24y = 31.36 . . . (3)
(2) x 4 => 2.24x - 2.24y = 17.92 . . . (4)
(3) - (4) => 4.48y = 13.44
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x = 3.52/0.32 = 11

Therefore, the speed of the current is 3 miles per hour. Answer is 3 miles per hour

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3 years ago

Read 2 more answers