IXL - Write linear, quadratic, and exponential functions from tables (Algebra 1 practice)

Look at this table:

x	y
– 10	– 24
– 9	– 21
– 8	– 18
– 7	– 15
– 6	– 12

Write a linear

(

quadratic

(

or exponential

(

)

function that models the data.

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Learn with an example

question

Look at this table:

x	y
4	– 34
5	– 41
6	– 48
7	– 55
8	– 62

Write a linear

(

quadratic

(

or exponential

(

)

function that models the data.

key idea

You can determine if a function is linear, quadratic, or exponential by looking at the pattern of

-values.

solution

Since the

-values

in the table are consecutive, you can compare successive

-values

to determine which type of function the table describes.

You can test whether a function is linear by finding the differences between successive

-values,

which are called the first

differences.

If the first differences are all equal, the function is linear.

Find the first differences in the table.

x	y
4	– 34	– 7
5	– 41	– 7
6	– 48	– 7
7	– 55	– 7
8	– 62

Since the first differences are all

–

the function is linear

(

When the differences are the same, the slope

is equal to the common difference,

–

Now, plug in one of the points from the table and solve for

For example, use

(

–

)

–

Plug in

(

–

)

–

(

)

Plug in

(

–

)

–

Multiply

–

Multiply

–

Add 28 to both sides

Since

–

and

–

the function is

–

Looking for more? Try this:

$Confetti$

Excellent!

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Teacher tools

Work it out

Not feeling ready yet? These can help:

AA.4Identify linear, quadratic, and exponential functions from tables

L.7Slope-intercept form: write an equation from a table

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