Answer:
8
Step-by-step explanation:
Let's just call the number x for simplicity.
So, 7x is 8 less than x².
Putting this into an equation would look like this
x² - 8 = 7x
It looks like we'll have to factor this to solve. Before we do that we need to move the 7x to the left side so that everything is together.
x² - 7x -8 = 0
Now, we can proceed. To factor we first need to find the factors of -8.
The factors of -8 are
-2 ⋅ 4, -4 ⋅ 2, -1 ⋅ 8, 1 ⋅ -8.
We need to find the pair of factors that adds up to -7. The only ones that do are -1 and 8.
So now that we have these we can create a pair of binomials using them. This will give us the factored form of this equation.
( x + 1 ) ( x - 8 )
To find the solutions we will have to set them to 0 and solve each of these binomials individually.
x - 1 = 0
x = 1
So, one of the solutions is 1. It's not the one we want, since it's positive.
x - 8 = 0
x = 8
This is the one we want since it is positive.
Answer:
There are 62 acres of old growth trees
Step-by-step explanation:
You would need to find 0.2% of 31,000
Lets say 0.2% of 31,000 is Y
Y = 0.2/100
Y = 0.2 ÷ 100 x 31,000
Y= 62
Answer:
The bone is 14572 years old.
Step-by-step explanation:
There is 17% as much Carbon-14 in the ancient bones as from current bones and the decay constant is given as 0.0001216 for time in years.
The equation for radioactive decay is N = N₀ e^(-λt)
where t = time in years
λ = decay constant
N = final amount of carbon
N₀ = initial amount of carbon.
There is 17% as much Carbon-14 in the ancient bones as in current bones. So,
N = 17% of N₀
N = 0.17N₀
So, N/No = 0.17.
N = N₀ e^(-λt)
N/N₀ = e^(-λt)
0.17 = e^(-0.0001216t)
ln (0.17) = -0.0001216t
-0.0001216t = -1.7719568
t = -1.7719568/-0.0001216
t = 14572 years
Answer:
Step-by-step explanation:
Answer:
evaluated: 4.20873523
scientific notation: 4.20873523
*10^0
