CPM Homework Help : INT1 Problem 8-123

If $f(x) = 3(2)^x$ , evaluate the expressions in parts (a) through (c) below. Then complete parts (d) and (e).

$f ( - 1 )$

Hint (a):

Substitute $−1$ for $x$ and simplify.

$f(−1) = 3(2)^{−1}$

$=3\cdot\frac{1}{2}$

Answer (a):

$\frac{3}{2}$

$f ( 0 )$

Hint (b):

Refer to part (a).

$f ( 1 )$

Hint (c):

Refer to part (a).

What value of $x$ gives $f ( x ) = 12 ?$

Hint (d):

Substitute $12$ for $f(x)$ and solve for $x$ .

Answer (d):

$x = 2$

Where does the graph of this function cross the $x$ -axis? The $y$ -axis? Use this information to sketch the graph.

Hint (e):

A function crosses the $x$ -axis at $y = 0$ , and a function crosses the $y$ -axis at $x = 0$ .

Use the eTool below to find the value of each expression in parts (a) through (c).
Click on the link at right for the full eTool version: Int1 8-123 HW eTool.