IXL | Write a linear function from a table

Fill in the missing number to complete the linear equation that gives the rule for this table.

x	y
2	30
3	31
4	32
5	33

y = x +

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Learn with an example

question

Fill in the missing number to complete the linear equation that gives the rule for this table.

x	y
3	40
4	41
5	42
6	43

y = x +

key idea

Linear functions are of the form y = mx + b.

solution

First find m. Look at the table and notice that every time the x terms go up by 1, the y terms go up by 1. This means that m is equal to 1.

x	y
3	40
4	41
5	42
6	43

Next find b. Take the equation y = mx + b and plug in the m value (m = 1) and a pair of (x, y) coordinates from the table, such as (3, 40). Then solve for b.

mx + b

Plug in m = 1, x = 3, and y = 40

1(3) + b

Plug in m = 1, x = 3, and y = 40

Simplify

3 + b

Simplify

Finally, use the m and b values you found (m = 1 and b = 37) to write the equation.

mx + b

Plug in m = 1 and b = 37

1x + 37

Plug in m = 1 and b = 37

Simplify

x + 37

Simplify

Now check your answer. Plug in each (x, y) pair in the table, and see if the result is a true statement.

Plug in (3, 40).

x + 37

3 + 37

Plug in (4, 41).

x + 37

4 + 37

Plug in (5, 42).

x + 37

5 + 37

Plug in (6, 43).

x + 37

6 + 37

Each (x, y) pair from the table resulted in a true statement.

So, the linear equation is y = x + 37.

Looking for more? Try these:

Lesson: Linear functions

Lesson: Slope

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Not feeling ready yet? These can help:

AA.9Write a linear equation from two points

Z.3Find the slope from a table

Lesson: Linear functions

Lesson: Slope

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