18. Select all the expressions equivalent to 12 + 30y.

Mathematics

1 answer:

bezimeni [28]3 years ago

3 0

A, B, and C are correct. D and E are incorrect

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2b-3/b-2 = 3b/b+2 ... Solutions by cross multiplying

Rzqust [24]

Step-by-step explanation:

(2b-3)/(b-2)(b+2) = 3b(b-2)/(b+2)(b-2)

2b²+4b-3b-6/b²-4=3b²-6b/b²-4

2b²+b- 6= 3b²-6b

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-b²+7b-6/b²-4

i also dk this is true or false

5 0

3 years ago

A researcher wishes to estimate, with 9090% confidence, the proportion of adults who have high-speed Internet access. Her es

Sunny_sXe [5.5K]

Answer: a) Required minimum sample size= 219

b) Required minimum sample size= 271

Step-by-step explanation:

As per given , we have

Margin of error : E= 5% =0.05

Critical z-value for 90% confidence interval : $z_{\alpha/2}=1.645$

a) Prior estimate of true proportion: p=28%=0.28

Formula to find the sample size :-

$n=p(1-p)(\dfrac{z_{\alpha/2}}{E})^2\\\\=0.28(1-0.28)(\dfrac{1.645}{0.05})^2\\\\=218.213856\approx219$

Required minimum sample size= 219

b) If no estimate of true proportion is given , then we assume p= 0.5

Formula to find the sample size :-

$n=0.5(1-0.5)(\dfrac{z_{\alpha/2}}{E})^2\\\\=0.25(\dfrac{1.645}{0.05})^2\\\\=270.6025\approx271$

Required minimum sample size= 271

8 0

3 years ago

What is the sum of the interior angles of the polygon shown below

DanielleElmas [232]

Answer:

720 degrees.

Step-by-step explanation:

The sum of the interior angles of a convex polygon with n sides is

180(n - 2) degrees.

In this case, n = 6 sides, so the angle sum is

180(6 - 2) = 180(4) = 720 degrees.

The reason this works is that if you draw a diagonal from one vertex to the others (see attached image), you get 2 fewer triangles than the number of sides. Each triangle contains a total of 180 degrees, so the total of all the interior angles is 180(n - 2).