Answer:
4) 0.001
Step-by-step explanation:
The amount (a) present in h hours is ...
a(h) = (initial value)×(1/2)^(h/(half-life))
6 days is 6×24 hours, so the amount remaining is ...
a(6×24) = 50×(1/2)^(6×24/9) = 50/2^16 ≈ 0.001 . . . . milligrams
You are right all the way
2 = 1.313 is the right answer
3 = 24 is the right answer
4 = 27 is the right answer
Answer:
Step-by-step explanation:
<u>Given equation:</u>
- x² + y² + 8x - 4y - 7 = 0
<u>Convert this to standard form by completing the square:</u>
- (x - h)² + (y - k)² = r², where (h, k) - center, r - radius
- x² + 2*4x + 4² + y² - 2*2y + 2² - 16 - 4 - 7 = 0
- (x + 4)² + (y - 2)² - 27 = 0
- (x + 4)² + (y - 2)² = 27
- (x + 4)² + (y - 2)² = (√27)²
The center is (- 4, 2) and the radius is √27
