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
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
Since the largest power of x is an odd number, the range is
.
Edwin