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AURORKA [14]
3 years ago
7

What's the standard equation of the circle with the general equation x2 + y2 + 4x – 2y – 20 = 0? answers: 1) (x + 2)2 + (y – 1)2

= 5 2) (x – 2)2 + (y + 1)2 = 25 3) (x + 1)2 + (y – 2)2 = 5 4) (x + 2)2 + (y – 1)2 = 25
Mathematics
1 answer:
gizmo_the_mogwai [7]3 years ago
3 0

Answer:

4).  (x + 2)^2 + (y - 1)^2 = 25.

Step-by-step explanation:

x^2 + y^2 + 4x - 2y - 20 = 0

x^2 + 4x + y^2 - 2y = 20

Completing the square on the x and y terms:

(x + 2)^2  - 4 + (y - 1)^2 - 1 = 20

(x + 2)^2 + (y - 1)^2 = 20 + 4 + 1

(x + 2)^2 + (y - 1)^2 = 25.

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Well first you would start by setting up with a proportion.
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5 0
3 years ago
Read 2 more answers
27. In a school of 500 students, 125 like chess and 160 like badminton. 45 students like chess and badminton both. Find how many
ozzi

Answer:

170

Step-by-step explanation:

Add 160 and 45 and 125

Then subtract it to the total number of students

So 500 minus 330

5 0
4 years ago
A customer service phone line claims that the wait times before a call is answered by a service representative is less than 3.3
Vika [28.1K]

Answer:

(A) Yes, since the test statistic is in the rejection region defined by the critical value, reject the null. The claim is the alternative, so the claim is supported.

Step-by-step explanation:

Null hypothesis: The wait time before a call is answered by a service representative is 3.3 minutes.

Alternate hypothesis: The wait time before a call is answered by a service representative is less than 3.3 minutes.

Test statistic (t) = (sample mean - population mean) ÷ sd/√n

sample mean = 3.24 minutes

population mean = 3.3 minutes

sd = 0.4 minutes

n = 62

degree of freedom = n - 1 = 62 - 1 = 71

significance level = 0.08

t = (3.24 - 3.3) ÷ 0.4/√62 = -0.06 ÷ 005 = -1.2

The test is a one-tailed test. The critical value corresponding to 61 degrees of freedom and 0.08 significance level is 1.654

Conclusion:

Reject the null hypothesis because the test statistic -1.2 is in the rejection region of the critical value 1.654. The claim is contained in the alternative hypothesis, so it is supported.

5 0
3 years ago
Architects make scale models of buildings to present their ideas to clients. If an
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The area of the model is 80 square foot

Step-by-step explanation:

Let the area of the house model be 'a'

The scale = 1:50

The area of the house= 4000 square foot

Area of the model =4000/50

a = 80 square foot

The area of the model is 80 square foot

5 0
4 years ago
Express 0.000089 in scientific notation
MrRissso [65]
8.9 x 10^-5 in scientific notation
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4 years ago
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