What is the value of x in the equation below?
2 answers:
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Answer: B. Jonesville is growing linearly and Smithville is growing exponentially.
Step-by-step explanation:
Linear growth :
- Population grow by a constant amount after each time period.
- The rate of change of dependent variable with respect to independent variable is a constant.
- It is represented by line on graph.
- Equation for linear growth :
, c = initial value and m is the rate of change of y with respect to x.
Exponential growth :
- Population grow by a constant ratio .
- It is represented by a curve on graph.
- Equation for exponential growth :
, a = initial value and r is rate of growth ( in decimal ) and x is time period.
Given : Jonesville's population grows by 170 people per year.
i.e .Population grow by a constant amount per year.
⇒ Jonesville is growing linearly.
The population of smithville grows by 7% per year.
i.e. Population grow by a constant ratio.
⇒Smithville is growing exponentially.
Hence, the true statement is "B. Jonesville is growing linearly and Smithville is growing exponentially."
The given function is a quadratic equation. Any quadratic equation can be written in the form :
The given points can be taken as (2,23) ,(4,55) and(10,247)
We form three equations with the given points
For point (2,23 ) the equation is
23 = 4a + 2b + c
For point (4,55) the equation is
55 = 16a + 4b + c
For point (10,247) the equation is:
247 = 100a+10b+c.
Solving the three equations for a,b,c we have :
32 = 12a + 2b
16 = 6a + b
and,
192 = 84 a + 6b
32 = 14a + b
Solving for a,b,c we have:
a=2 b=4 c=7
The quadratic equation is c(x)=
When x=8
c(x)=]
Option C. $167 is the right answer.