IXL - Exponential growth and decay (Algebra 2 practice)

Does this function represent exponential growth or exponential decay?

(

0.82

)

exponential growth

exponential decay

ref_doc_title.

Learn with an example

question

Does this function represent exponential growth or exponential decay?

x	y
– 1	100
0	200
1	400
2	800
3	1,600

exponential growth

exponential decay

key idea

An exponential function of the form

(

)

(with

and

≠

)

models exponential growth or decay.

The constant
a
is the initial value. It is the
y
-value
when
x
=
0
.
The constant
b
is the growth or decay factor. Each time
x
increases by 1,
y
is multiplied by
b
.

The function models exponential growth when

The

-values

increase as the

-values

increase, and the graph resembles a J-shaped curve.

The function models exponential decay when

The

-values

decrease as the

-values

increase, and the graph resembles a backwards J-shaped curve.

solution

To determine if the function represents exponential growth or decay, find

See which number

is multiplied by each time

increases by 1.

x	y
– 1	100	× 2
0	200	× 2
1	400	× 2
2	800	× 2
3	1,600

The table shows

Since

the function represents exponential

growth.

Looking for more? Try these:

Lesson: Exponential growth

Lesson: Exponential decay

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Teacher tools

Work it out

Not feeling ready yet? These can help:

Z.3Write exponential functions: word problems

Lesson: Exponential growth

Lesson: Exponential decay

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