C = pi * d
a = pi * (d/2)^2
Answer:
9x² − 12x + 4
Step-by-step explanation:
A perfect square trinomial:
a² + 2ab +b²= (a + b)²
a² - 2ab +b²= (a - b)²
9x² − 12x + 4 = (3x)² - 2*(3x)*2 + 2² = (3x - 2)²
36b² − 24b + 16
16x² − 24x − 9
4a² − 10a − 25
Step-by-step explanation:
so, that means we want to find the time t (days) after which N = No/2
because "half-life" means the amount of time until half of the substance has disappeared (or transformed into something else).
so, we have
No/2 = No × e^(-0.1481×t)
No = 2× No × e^(-0.1481×t)
1 = 2×e^(‐0.1481×t)
1/2 = 0.5 = e^(-0.1481×t)
ln(0.5) = -0.1481×t
t = ln(0.5)/-0.1481 = 4.680264555... ≈ 4.7 days
I think the answer is b -3.
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