SOLUTION: The national cost C in billions of dollars for dental services can be modeled by the linear equation C= 2.85n + 3052, where n is the number of years since 1990. a) find and interp

Algebra.Com
Question 182660: The national cost C in billions of dollars for dental services can be modeled by the linear equation C= 2.85n + 3052, where n is the number of years since 1990.
a) find and interpret the C-intercept for the line
b) find and interpret the n-intercept for the line
c) graph the line for n ranging from 0 through 20
d) if this trend continues, then in what year will the cost of dental services reach 100 billion?
This is what I have so far for an answer:
I tried to solve for C. I began by subtracting 1990 from this current year 2009 which gave me 19, so n=19. Then I was able to solve for C.
C= 2.85(19) + 3052
C= 54.15 + 30.52
C= 84.67
a) n=0, then C=2.85(0) + 30.52. C-intercept is (0, 30.52)
b) C=0, then 2.85n + 30.52 = 0 Here's my work for this equation:
2.85n + 30.52 - 30.52 = 0 -30.52
2.85n/2.85 = -30.52/2.85
n=-10.70
n-intercept is (-10.70, 0) or is the n-intercept (19, 84.67)?
d)I think I have to substitute C for 84.67 which will allow me to solve the equation for n. Below is what I did.
C= 2.85n + 30.52
8467= 2.85n + 30.52
-30.52 - 30.52
54.15= 2.85n
54.15/2.85 = 2.85n/2.85
n=19
So will the year be 2019 since n=19?

Answer by Mathtut(3670)   (Show Source): You can put this solution on YOUR website!
A) Find and interpret the C-intercept for the line
C = 2.85n + 30.52
:
C = 2.85(0) + 30.52
C = 30.52......(0,30.52)
At zero years, the C-intercept is at $30.52 billion.
B)Find and interpret the n-intercept for the line
C = 2.85n + 30.52
0 = 2.85n + 30.52
-30.52 = 2.85n
-30.52/285 = n
-10.70= n (-10.70,0) remember in an x intercept(n in our case) y is always zero.
n intercept means in 1979 , the cost was zero.
C)Graph the line for n ranging from 0 through 20

D If this trend continues, then in what year will the
cost of dental services reach 100 billion?
C = 2.85n + 30.52
100 = 2.85n + 30.52
69.48 = 2.85n
About 24.37 years later:
so between 24 and 25 years it will reach 100 billion
Year: 2014-2015

RELATED QUESTIONS

Dental services- The national cost c in billions of dollars for dental services can be... (answered by JBarnum)
Dental services. The national cost C in billions of dollars for dental services can be... (answered by Mathtut)
Dental Services: The national cost C in billions of dollars for dental services can be... (answered by stanbon)
The national cost C in billions of dollars for dental services can be modeled by the... (answered by stanbon)
the national cost C in billions of dollars for dental service can be modeled by the... (answered by Nate)
National cost in billions of dollars for dental services can be modeled by the linear... (answered by strickjh2005)
The national cost C in billions of dollars for dental services can be modeled by C=2.85n... (answered by nabla)
I have seen this problem on here but I am not understanding why they use zero for "n"... (answered by stanbon)
The national cost C in billions of dollars for dental services can be modeled by the... (answered by stanbon)