What is the radius of the circle with an equation of x2 - 12x + y2 + 4y = -4?
2 answers:
Answer:
radius = 6
Step-by-step explanation:
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 is the radius
Given
x² - 12x + y² + 4y = - 4
Using the method of completing the square on the x and y terms
add (half the coefficient of the x/y term )² to both sides
x² + 2(- 6)x + 36 + y² + 2(2)y + 4 = - 4 + 36 + 4, that is
(x - 6)² + (y + 2)² = 36 ← in standard form
with r² = 36 ⇒ r = = 6
You might be interested in
Since <em>N</em>/2 leaves a remainder, <em>N</em> must be odd and ends with 1, 3, 5, 7, or 9.
<em>N</em>/5 also leaves a remainder, so <em>N</em> is not divisible by 5, so it does not end in 5.
The only correct choice is then 9, since
1 = 0•5 + 1 and 1 = 0•2 + 1
3 = 0•5 + 3 and 3 = 1•2 + 1
7 = 1•5 + 2 and 7 = 3•2 + 1
9 = 1•5 + <u>4</u> and 9 = 4•2 + <u>1</u>
<u />
Alternatively, the given information is equivalent to saying
Then you can use the Chinese remainder theorem to find <em>N</em>.
Answer:
<u>After (3/2) months Tyler's gym would be a better deal.</u>
Step-by-step explanation:
Let x the number of months
Cody's Gym charges a $15 fee to join and $30 per month
y₁= 15 + 30x (1)
Tyler's Gym charges a $30 fee to join and $20 per month
y₂ = 15 + 30x (2)
See the attached figure which represent the graph of y₁ (with blue color) and y₂ (with red color)
The point of intersection between y₁ and y₂ is ( 3/2 , 60)
After 3/2 months Tyler's Gym charges will be less than Cody's Gym charges
So, the inequality will be:
<u>After (3/2) months Tyler's gym would be a better deal.</u>
