IXL - Write linear and exponential functions: word problems (Algebra 1 practice)

Sam's football team is selling coupon books for

each to raise funds for new jerseys. You can use a function to describe the amount of money the team brings in from selling

coupon books.

Is the function linear or exponential?

linear

exponential

Which equation represents the function?

(

)

(

)

ref_doc_title.

Learn with an example

question

Ben is selling candles to raise money for an out-of-state trip with his business club. He already has

145

in donations and will earn an additional

for every candle he sells. You can use a function to describe the total amount of money Ben will have for his trip after he sells

candles.

Is the function linear or exponential?

linear

exponential

Which equation represents the function?

(

)

145

(

)

(

)

145

key idea

Linear functions have a constant rate of change—they change by equal differences over equal intervals. Linear functions can be written in this form, where

is the rate of change and

is the initial value:

(

)

Exponential functions do not have constant rates of change. Instead, they change by equal factors or percentages over equal intervals. Exponential functions can be written in this form, where

is the initial value

(

≠

)

and

is the growth factor

(

≠

(

)

(

)

solution

Ben will earn

for each candle he sells. So, for every additional candle he sells, the total amount of money he will have for his trip increases by

That is a constant rate of change, so the function

(

)

linear.

Now, identify

and

in the equation

(

)

The rate of change is
$
10
per candle. So,
m
=
10
.
Before Ben started selling candles, he already had
$
145
in donations. So,
b
=
145
.

Finally, write the equation.

(

)

(

)

Plug in

and

145

Plug in

and

145

Looking for more? Try these:

Lesson: Exponential growth

Lesson: Exponential decay

Lesson: Linear functions

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Teacher tools

Work it out

Not feeling ready yet? These can help:

V.8Write exponential functions: word problems

N.8Write a linear function: word problems

Lesson: Exponential growth

Lesson: Exponential decay

Lesson: Linear functions

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