(2n+1)(2n-1)(n+5)
=(4n^2+2n-2n-1)(n+5)
=(4n^2-1)(n+5)
=4n^3-n+20n^2-5
4n^3+20n^2-n-5
Answer:
D. About 800 years
Step-by-step explanation:
Use the half-life equation:
A = A₀ (½)ⁿ
where A is the final amount,
A₀ is the initial amount,
and n is the number of half-lives.
0.90A₀ = A₀ (½)ⁿ
0.90 = (½)ⁿ
To solve for n, take log of both sides:
log 0.9 = n log 0.5
n = (log 0.9) / (log 0.5)
n = 0.152
It takes 0.152 half-lives. The half-life of carbon-14 is 5730 years.
0.152 × 5730 years = 871 years
The closest answer is D.
(d): y = mx+n
m = -2/3 ⇒ y = (-2/3)x +n
A(-4, 6) ∈ d ⇒ 6 = (-2/3)·(-4) +n ⇒ 6 = 8/3 +n ⇒
⇒ n = 6 - 8/3 ⇒ n = 10/3
Now, we have:
y = (-2/3)x +10/3
Can u take a picture please?
25 because Becky read 45 and Jason read 20
45-20 = 25
