Answer:f(-2)=2
Step-by-step explanation:
-x^2-5x-4
= -(-2)^2-5(-2)-4
= -4+10-4
= 2
For this case, the first thing we must do is define variables.
We have then:
x: Maggie's age
y: Age of Maggie's brother
We write the system of equations that models the problem.
We have then:
We solve the system of equations.
For this, we use substitution:
From here, we clear the value of x:
Answer:
Maggie is 9 years old
The function for the amount saved if they purchase a used drone rather than a new drone from Jim's store is f(x) = 0.45x
He sells used drones at 70% of the price (x).
So, the selling price of a used drone is:
Express percentage as decimal
Also, he sells new drones at 15% more of the price (x).
So, the selling price of a new drone is:
Express percentage as decimal
The amount saved is the difference between the prices of the drones.
So, we have:
This gives
Subtract
Express as a function
Hence, the function for the amount saved is f(x) = 0.45x
Read more about proportions at:
brainly.com/question/13114933
Answer:
Step-by-step explanation:
given that the annual consumption of beef per person was about 64.9 lb in 2000 and about 60.7 lb in 2007.
Assume B(t), the annual beef consumption t years after 2000, is decreasing according to the exponential decay model
i.e. , where t is the number of years from 2000
B0 = quantity in 2000 = 64.9
So the equation is
When t =7, B(7) = 60.7
Substitute to solve for k
So equation woul dbe
c) B(t) = 30 gives
i.e. in the year 2080