I did some math and i got this
x = -2
Answer:
Step-by-step explanation:
Answer:
b = d/(2ac)
Step-by-step explanation:
10abc - 2d = 3d
Add 2d to each side
10abc - 2d+2d = 3d+2d
10 abc = 5d
Divide each side by 10ac
10 abc/ (10ac) = 5d/10ac
b = d/(2ac)
The empirical rule states that in a normal distribution,
68% of data is within 1 std deviation of the mean
95% of data is within 2 std deviation of the mean
99.7% of data is within 3 std deviation of the mean
In this case 95% of the cases would be within two std deviations of the mean
mean - 8 and mean + 8
72 - 8 = 64 and 72 + 8 = 80
then 95% of the scores are between 64% and 80% on the test.
Using an exponential function, it is found that it takes 18.6 days for 80% of the material to decay.
The amount of a substance after t days is modeled by:
In which:
- k is the decay rate, as a decimal.
- A(0) is the initial amount.
The half-life is of 8 days, hence 
, and this is used to find k.
Hence:
The time it takes for 80% of the material to decay it t for which 
, hence:
It takes 18.6 days for 80% of the material to decay.
To learn more about exponential functions, you can take a look at brainly.com/question/24906920
