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vichka [17]
3 years ago
8

REALLY NEED HELP, PLEASE HELP ME

Mathematics
1 answer:
sveta [45]3 years ago
6 0

x^2 + y^2 -8x -6y +21 = 0

centre = -(-8)/2, -(-6)/2

= 4, 3

radius = √(4^2) + 3^2 - 21

= √(16 +9 -21)

= √(25 -21)

= √4

= 2

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Write4×4×4×4 in index​
JulijaS [17]

Answer:

4^4

Step-by-step explanation:

the answer is 4 to the power of 4

5 0
2 years ago
Construct the confidence interval for the population mean mu. c = 0.90​, x = 16.9​, s = 9.0​, and n = 45. A 90​% confidence inte
Georgia [21]

Answer:

The  90%  confidence interval for population mean is   14.7  <  \mu  <  19.1

Step-by-step explanation:

From the question we are told that

   The sample mean is  \= x  =  16.9

    The confidence level is  C  =  0.90

     The sample size is  n  =  45

     The standard deviation

Now given that the confidence level is  0.90 the  level of significance is mathematically evaluated as

       \alpha =  1-0.90

       \alpha  =  0.10

Next we obtain the critical value of  \frac{\alpha }{2}  from the standardized normal distribution table. The values is  Z_{\frac{\alpha }{2} } =  1.645

The  reason we are obtaining critical values for \frac{\alpha }{2}  instead of  that of  \alpha  is because \alpha  represents the area under the normal curve where the confidence level 1 - \alpha (90%)  did not cover which include both the left and right tail while \frac{\alpha }{2}  is just considering the area of one tail which is what we required calculate the margin of error

  Generally the margin of error is mathematically evaluated as

        MOE  =  Z_{\frac{\alpha }{2} } *  \frac{\sigma }{\sqrt{n} }

substituting values

         MOE  = 1.645*  \frac{ 9 }{\sqrt{45} }

         MOE  = 2.207

The  90%  confidence level interval is mathematically represented as

      \= x  -  MOE  <  \mu  <  \= x  +  MOE

substituting values

     16.9 -  2.207  <  \mu  <  16.9 +  2.207

    16.9 -  2.207  <  \mu  <  16.9 +  2.207

     14.7  <  \mu  <  19.1

         

3 0
3 years ago
9 t-shirts and a hat costs £93 4 t-shirts and a hat costs £43 how much does the hat and t-shirt cost
alexandr402 [8]

Answer:

T-shirt costs £10

Hat costs £3

Step-by-step explanation:

£93-£43=£50

9-4=5

£50/5=10

1 t-shirt=£10

£10x9=£90

£93-£90=£3

T-shirt = £10

Hat= £3

4 0
3 years ago
Read 2 more answers
A tire on a toy car has a diameter of 8 cm if the toy car travels 12,560 cm approximately how many times does the tire rotate? U
Marina86 [1]

Answer:

The number of rotations completed by tire  = 500.

Step-by-step explanation:

The diameter of the tire of toy car = 8 cm

Now, DIAMETER = 2 x RADIUS

So, radius of the tire =  D/2  = 8/2 = 4 cm

Now, Circumference of the Circle = 2πr

= 2 x 3.14 x 4 = 25.12 cm

Now, \textrm{Total  number of rotations}  = \frac{\textrm{Total Area covered}}{\textrm{Area covered in 1 rotation}}

= \frac{12,560}{25.12}  = 500

The number of rotations completed by circle = 500.

6 0
3 years ago
Which function has a minimum and is transformed to the right and down from the parent function, f(x) = x2? g(x) = –9(x2 + 2x + 1
nata0808 [166]
D. Last Answer is the correct answer to your question
8 0
3 years ago
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