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valentina_108 [34]

2 years ago

8

The temperature dropped 20 degrees from noon to midnight. The temperature at midnight was 24°F. Write and solve an equation to f

ind the temperature at noon?

1 answer:

dezoksy [38]2 years ago

6 0

X - 20 = 24

Add 20 to both sides

x = 24 + 20 = 44

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Solve by substitution x-y=-11 y+7=-2x

Bess [88]

x - y = - 11 .............( 1 )

y + 7 = - 2x ...............( 2 )

from equation ( 1 )

x - y = - 11

x = -11 + y ...........( 3)

putting x in equation ( 2 )

y + 7 = - 2 x

y + 7 = -2 ( -11 + y ) y + 7 = 22 - 2 y y + 2 y =22 - 7

3 y = 15 y = 15 / 3

putting value of y in equation 3

x = -11+ ( 13 /5 ) x = -33 /3 + 15 / 3 ( l.c.m)

x = -17 / 5

check

x = -11 + y

- 17 / 5 = -11 + 13 / 5

-17 /5 = -17 / 5

4 0

2 years ago

A researcher wishes to estimate, with 99% confidence, the population proportion of adults who think the president of their co

scoray [572]

Answer:

a. n=4148

b. n=3909

c. The sample size is smaller if a known proportion from prior study is used. The difference in sample sizes is 239

Step-by-step explanation:

a. For sample where no preliminary estimate is given, the minimum sample size is calculated using the formula:

$n=p(1-p)(\frac{z}{ME})^2$

Where:

$ME=$ Margin of error
$p=$ is the assumed proportion

#Let p=0.5, substitute in the formula to solve for n:

$n=0.5(1-0.5)\times (2.576/0.02)^2\\\\=4147.36\approx 4148$

Hence, the minimum sample size is 4148

b. If given a preliminary estimate p=0.38, we use the same formula but substitute p with the given value:

$n=p(1-p)(z/ME)^2\\\\=0.38(1-0.38)(2.576/0.02)^2\\\\=3908.47\approx3909$

Hence, the minimum sample size is 3909

c. Comparing the sample sizes from a and b:

$n_{0.5}>n_{0.38}\\\\n_{0.5}-n_{0.38}=4148-3909=239$

Hence, the actual sample size is smaller for a known proportion from prior a prior study.

8 0

3 years ago

Find a polynomial equation that has double zeros at x = -1, and x = 8.

blondinia [14]

Answer:

x^2-7x+8=0

Step-by-step explanation:

(x+1)(x-8)=0

x^2-7x+8=0

3 0

2 years ago

Read 2 more answers

A car travels 81 miles in 3 hours. If it continues traveling at the same rate, how many miles would it travel in 5 hours?

wel

The car would travel 135 miles bc you multiply 81×5 and get 405 ,then divide that answer by 3

8 0

2 years ago

525$deposit. 4% interest. 1 year. calculate the simple interest earnef

elena55 [62]

First you will divide 525 by 100. Then you multiply your answer by 4. That will equal 21

6 0

3 years ago