Answer:
centre = (2, - 1), radius = 6
Step-by-step explanation:
Rearrange the equation by placing the x and y terms together and adding 31 to both sides
Given
x² + y² - 4x + 2y - 31 = 0, then
x² - 4x + y² + 2y = 31
Use the method of completing the square
add ( half the coefficient of the x/y term )² to both sides
x² + 2(- 2)x + 4 + y² + 2(1)y + 1 = 31 + 4 + 1
(x - 2)² + (y + 1)² = 36
The equation of a circle in standard form is
(x - h)² + (y - k)² = r²
where (h, k) are the coordinates of the centre and r the radius
compare to (x - 2)² + (y + 1)² = 36, then
centre = (2, - 1) and r = 
= 6
A.9
B.12
C.2
D.5
E.7.4
F.5 2/3 or 5.6666
The student with the correct answer is Dylan who says the decimal should be placed between the 8 and 0.
This is base on the estimation that 3.01 is a two decimal place number, so the product 18.06 should also be in 2 decimal place.
<h3>How to find product of decimal number?</h3>
A decimal number is a number expressed in the decimal system (base 10).
Place value:
- Ten thousand
- Thousand
- Hundred
- Ten
- ones
- . decimal point
- tenth
- hundredths
- thousandth
- ten thousandth
- hundred thousandth
6 × 3.01
3.01
- 3 = ones
- . = decimal point
- 0 = tenth
- 1 = hundredth
6 × 3.01
= 18.06
Therefore, Lucas is incorrect with his answer that the decimal should be placed between the 1 and 8.
Read more on decimal number:
brainly.com/question/1827193
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The minimum number of T-shirt that they must sell to raise $500 is 67 T-shirts
Let x represent the number of Pi Day T-shirts sold.
They are selling Pi Day T-shirts for $7.50 each, So to raise $500:
7.5x > 500
Dividing through by 7.5:
7.5x / 7.5 > 500 / 7.5
x > 66.7
Hence, the minimum number of T-shirt that they must sell to raise $500 is 67 T-shirts
Find out more at: brainly.com/question/25285332
