SOLUTION: Given: f(x)=8-5x A. Find f(-2) B. Find x, when f(x)=8 C. State the domain and range of the function

Algebra ->  Functions -> SOLUTION: Given: f(x)=8-5x A. Find f(-2) B. Find x, when f(x)=8 C. State the domain and range of the function       Log On


   



Question 1082884: Given: f(x)=8-5x
A. Find f(-2)
B. Find x, when f(x)=8
C. State the domain and range of the function

Answer by Edwin McCravy(20054) About Me  (Show Source):
You can put this solution on YOUR website!
Given: f(x)=8-5x
A. Find f(-2)
f(x)=8-5x

Everywhere there is an x, substitute (-2) instead:

f(-2) = 8-5(-2)

Simplify

f(-2) = 8+10

f(-2) = 18

B. Find x, when f(x)=8
f(x)=8-5x

Everywhere there is an f(x), substitute 8 instead:

8=8-5x

Solve for x

Subtract 8 from both sides

0=-5x

Divide both sides by -5

0%2F%28-5%29=%28-5x%29%2F%28-5%29

0=%28cross%28-5%29x%29%2Fcross%28-5%29

0=x

C. State the domain and range of the function
Since there are no denominators or square roots,
or special functions, such as absolute values, the domain 
is always %28matrix%281%2C3%2C-infinity%2C%22%2C%22%2Cinfinity%29%29 

Since the largest power of x is an odd number, the range is
%28matrix%281%2C3%2C-infinity%2C%22%2C%22%2Cinfinity%29%29.

Edwin