In the problem with the white circle, x=100, in the problem with the blue circle, x might equal 165, but I'm not entirely certain. But I am certain about the first one.
Answer:

Step-by-step explanation:

Hope this helped!! Have an amazing day :D
A)46. Take 42 and divide it by 3. Then multiply 14 by 4.
b)2:1. There are 2 wings for every 1 beak on a bird.
c)15 minutes. multiply 50 times 60 and that's how many times it beats per minute. Then divide 45000 by that number and that's how many minutes it should take.
d) 28%. You have to add all the students together, and you get 200. Then you divide 56 by 200.

★ <u>Option (A) y = -5x</u> is the right answer.
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I hope this helps! :)</h3>
Answer:
If y(t) is the mass (in mg) remaining after t years, then y(t) = y(0) (0.5)^{t/T} = 400 (0.5)^{t /4}, where T is the half-life period and y(0) is the amount at t = 0 years (initial).
Then at t = 20:
y(20) = 400 (0.5)^{20 /4} = \text{12.5 mg}
Step-by-step explanation: