Answer:
Step-by-step explanation:
x² - 2x + y² - 4y - 4 = 0
x² - 2x + y² - 4y = 4
complete the squares
(x² - 2x + x₀) + (y² - 4y + y₀) = 4
the unknown number will be the square of half of the x¹ coefficient
(x² - 2x + 1) + (y² - 4y + 4) = 4 + 1 + 4
(x - 1)² + (y - 2)² = 9
This tells us that the circle is centered on (1, 2)
Which is also a point on the diameter
2x - y + a = 0
a = y - 2x
a = 2 - 2(1)
a = 0
Answer:
Exponents first then multiplication then subtraction
Answer:
Answer is D. 1572 square units.
You know that;
Maggie has finished 30% of 50
50*(30/100)
=15 puzzles done
Left to do: 50-15=35
Hope I helped :)
Answer:C. (77.29, 85.71)
Step-by-step explanation:
We want to determine a 95% confidence interval for the mean test score of randomly selected students.
Number of sample, n = 25
Mean, u = 81.5
Standard deviation, s = 10.2
For a confidence level of 95%, the corresponding z value is 1.96. This is determined from the normal distribution table.
We will apply the formula
Confidence interval
= mean +/- z ×standard deviation/√n
It becomes
81.5 +/- 1.96 × 10.2/√25
= 81.5 +/- 1.96 × 2.04
= 81.5 +/- 3.9984
The lower end of the confidence interval is 81.5 - 3.9984 =77.5016
The upper end of the confidence interval is 81.5 + 3.9984 =85.4984
Therefore, the correct option is
C. (77.29, 85.71)
