The table represents an exponential function.

A 2-column table has 4 rows. The first column is labeled x with entries 1, 2, 3, 4. The second column is labeled y with entries three-halves, nine-eigths, StartFraction 27 Over 32 EndFraction, StartFraction 81 Over 128 EndFraction.

What is the multiplicative rate of change of the function?

Two-thirds
Three-fourths
Four-thirds
Three-halves

1 answer

To find the multiplicative rate of change (also known as the common ratio) of the exponential function given in the table, we need to determine how the value of \( y \) changes as \( x \) increases.

The given points are:
\( (1, \frac{3}{2}) \)
\( (2, \frac{9}{8}) \)
\( (3, \frac{27}{32}) \)
\( (4, \frac{81}{128}) \)

Let's find the common ratio \( r \) by dividing successive \( y \)-values:

1. From \( x = 1 \) to \( x = 2 \):
\[ \frac{\frac{9}{8}}{\frac{3}{2}} = \frac{9}{8} \times \frac{2}{3} = \frac{9 \times 2}{8 \times 3} = \frac{18}{24} = \frac{3}{4} \]

2. From \( x = 2 \) to \( x = 3 \):
\[ \frac{\frac{27}{32}}{\frac{9}{8}} = \frac{27}{32} \times \frac{8}{9} = \frac{27 \times 8}{32 \times 9} = \frac{216}{288} = \frac{3}{4} \]

3. From \( x = 3 \) to \( x = 4 \):
\[ \frac{\frac{81}{128}}{\frac{27}{32}} = \frac{81}{128} \times \frac{32}{27} = \frac{81 \times 32}{128 \times 27} = \frac{2592}{3456} = \frac{3}{4} \]

We can see that the common ratio \( r \) is \( \frac{3}{4} \) in all cases.

Thus, the multiplicative rate of change of the function is **three-fourths**.