Remember that exponentioal rule
x^m times x^n=x^(m+n)
therefor
7^4 times 7^-6=7^(4-6)=7^(-2)
remember the other rule
x^-m=1/(x^m) so
7^-2=1/(7^2)=1/49
answe ris A
Answer:
son will receive 1,760
Step-by-step explanation:
given:
A man left 5720 to be shared among his son and 3 daughters. Each daughter's share was 3/4 of the son's share
find:
How much did the son receive?
solution:
sum of shares = 5720 = 1 son(s) + 3 daughters (d) ---------eq.1
each daughter 1(d)= 3/4(s)of son
from eq. 1:
5720 = 1s + 3d
substitute d = 3/4s into eq.1
5720 = 1s + 3 (3/4 s)
5720 = 1s + 9/4 s
5720 (4) = 13 s
s = 22880 / 13
s = 1760
therefore,
the son will receive 1,760
Answer:
a. U(a) = 20000·0.9^a
b. about -$957 dollars per year
c. 13 years
Step-by-step explanation:
a) The age values are sequential, but the differences between "v" values are not constant. We suspect an exponential function. When we examine the ratios of adjacent table values, we find they are all 0.9, so the exponential function will be ...
U = (initial value)·(0.9^(age))
U(a) = 20000·0.9^a
__
b) The average rate of change for the one year between age 7 and age 8 will be U(8) -U(7). A calculator evaluates that difference as -$956.59, about -$957.
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c) The car value drops by almost half in 6 years, so will drop by almost half of that in another 6 years. The car's age will be 12 or 13 years. A graph shows the age to be just over 13 years when the value is predicted to be $5000.
_____
A graphing calculator was used to evaluate the function and find the time associated with the given value. (See attached.) This is the "work" that was done to answer the questions.
The time to decrease to 1/4 of the original value can be found by solving ...
5000 = 25000·0.9^a
The solution is ...
a = log(.25)/log(0.9) ≈ 13.158 . . . . as found on the graph
time= distance/speed
take distance as d. take time as t.
the time taken: d/ 65 for the train however it is the same distance for d/130 so we can say (d/65)-3 = d/130
now solve the equation, multiply both sides by 130
2d-390=d
2d-d=390
so d=390 mi
Answer:
Decease in weight by 56.4%
Step-by-step explanation:
From 55 lb to 24 lb,
There is a decrease in the weight from 55 lb to 24 lb.
For the percentage decrease in weight,
Change in weight = 55 - 24
= 31 lb
Percentage change in weight =
=
= 56.36%
≈ 56.4%
Therefore, there is a decease in weight by 56.4%.