Answer: r=(-189)

first you subtract both sides by 8 and get -21=r/9

then you multiply 9 with each side and get -189 = r

you can check by rewriting the problem with -189 as r and solving the equation

7 0

3 years ago

Please Help Me! It’s Math! Please!

nadezda [96]

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.

8 0

3 years ago

Whats the anwser for 4n -8 =5

Charra [1.4K]

Step by step explanation

4n-8=5
4n= 5+8
4n=13
4/4 n = 13/4
n= 13/4

3 0

4 years ago

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