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3 years ago

What is (5-4b) (3-8b)

Mathematics

2 answers:

nadezda [96]3 years ago

6 0

(5 - 4b)(3 - 8b)
15 - 40b - 12b + 32b²
15 - 52b + 32b²

tester [92]3 years ago

5 0

15-40b-12b+32b^2 so your final answer in standard form would be 32b^2-52b+15

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A team is excavating an archeological site. The original plan was to excavate a rectangular area 35 ft long

nikitadnepr [17]

Answer:

Part 1) The length of the new rectangle is $87.5\ ft$

Part 2) The area of the new rectangle is $4,375\ ft^{2}$

Step-by-step explanation:

we know that

If two rectangles are similar, then the ratio of its corresponding sides is proportional

step 1

Find the length of the new rectangle

Let

L-----> the length of the new rectangle

$\frac{50}{20}=\frac{L}{35}\\ \\ L=50*35/20\\ \\L=87.5\ ft$

step 2

Find the area of the new rectangle

we know that

The area of the rectangle is

$A=LW$

we have

$L=87.5\ ft$

$W=50\ ft$

substitute

$A=(87.5)(50)=4,375\ ft^{2}$

3 0

3 years ago

For i^2 =-1, (3-i)^2 = ? A. 8 B. 10 C. 8-6i D. 8 + 6i E. 10-6i

Anuta_ua [19.1K]

C. 8- 6i
(3- i) to the power of 2 (expand the expression)

9- 6 i + i to the power of 2
calculate

9 - 6i - 1
calculate

8- 6i.

8 0

3 years ago

The answer is D Does not exist; does not exist

jolli1 [7]

Answer:

Have a great day too..... :)

7 0

3 years ago

What is the length of the missing side?

Anna [14]

Answer:

first one x = 26

second one x = 11.12

Step-by-step explanation:

a^2 + b^2 = c^2

24^2 + 10^2 = c^2

676 = c^2

26 = c

a^2 = c^2 - b^2

a^2 = 12^2 - 4.5^2

a^2 = 123.75

a = 11.12

4 0

3 years ago

In selecting a sulfur concrete for roadway construction in regions that experience heavy frost, it is important that the chosen

Lesechka [4]

Step-by-step explanation:

Given - In selecting a sulfur concrete for roadway construction in regions that experience heavy frost, it is important that the chosen concrete has a low value of thermal conductivity in order to minimize subsequent damage due to changing temperatures. Suppose two types of concrete, a graded aggregate and a no-fines aggregate, are being considered for a certain road. The table below summarizes data on thermal conductivity from an experiment carried out to compare the two types of concrete.

Type ni xi si

Graded 42 0.486 0.187

No-fines 42 0.359 0.158

To find - a. Formulate the above in terms of a hypothesis testing problem.

b. Give the test statistic and its reference distribution (under the null hypothesis).

c. Report the p-value of the test statistic and use it to assess the evidence that this sample provides on the scientific question of difference in mean conductivity of the two materials at the 5% level of significance.

Proof -

a.)

Hypothesis testing problem :

H0 : There is significant difference between mean conductivity for the graded concrete and mean conductivity for the no fines concrete.

H1 : There is no significant difference between mean conductivity for the graded concrete and mean conductivity for the no fines concrete.

Test statistic :

$Z = \frac{x_{1} - x_{2} }{\sqrt{\frac{s_{1} ^{2} }{n_{1}} + \frac{s_{2}^{2} }{n_{2}} } }$

$Z = \frac{0.486 - 0.359 }{\sqrt{\frac{0.03496 }{42} + \frac{0.02496 }{42} } }$

$Z = \frac{0.127 }{\sqrt{0.001468}}$

$Z = \frac{0.127 }{0.0377}$

⇒Z(cal) = 3.3687

Z(tab) = 1.96

As Z (cal) > Z(tab)

So, we reject H0 at 5% Level of significance

p-value = 0.99962

Hence

There is significant difference in mean conductivity at the two materials.

5 0

3 years ago