Grade 8 Function Table Worksheets 2024 - Free Printable

Let’s go through each function table one by one. We’ll plug in the given x-values into the function to find f(x), or vice versa — if we’re given f(x), we solve for x.

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1) f(x) = 7x

We are given some x and f(x) values, need to fill blanks.

- When x = 2 → f(x) = 7×2 = 14
- When f(x) = 21 → 7x = 21 → x = 3
- When x = 4 → f(x) = 7×4 = 28
- When x = 5 → f(x) = 7×5 = 35

✔ Table filled:
x: 2, 3, 4, 5
f(x): 7, 21, 28, 35

Wait — original table has:
x: __, 2, __, 4, 5
f(x): 7, __, 21, __, __

So let’s match properly:

Given:
- First column: f(x)=7 → 7x=7 → x=1
- Second: x=2 → f(x)=14
- Third: f(x)=21 → x=3
- Fourth: x=4 → f(x)=28
- Fifth: x=5 → f(x)=35

✔ Final table for #1:
x: 1, 2, 3, 4, 5
f(x): 7, 14, 21, 28, 35

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2) f(x) = -x - 8

Given:
x: -4, __, 8, __, 16
f(x): __, -12, __, -20, __

Compute missing:

- x = -4 → f(x) = -(-4) - 8 = 4 - 8 = -4
- f(x) = -12 → -x - 8 = -12 → -x = -4 → x = 4
- x = 8 → f(x) = -8 - 8 = -16
- f(x) = -20 → -x - 8 = -20 → -x = -12 → x = 12
- x = 16 → f(x) = -16 - 8 = -24

✔ Table:
x: -4, 4, 8, 12, 16
f(x): -4, -12, -16, -20, -24

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3) f(x) = 6 - 3x

Given:
x: -10, __, -6, __, -2
f(x): __, 30, __, 18, __

Compute:

- x = -10 → f(x) = 6 - 3(-10) = 6 + 30 = 36
- f(x) = 30 → 6 - 3x = 30 → -3x = 24 → x = -8
- x = -6 → f(x) = 6 - 3(-6) = 6 + 18 = 24
- f(x) = 18 → 6 - 3x = 18 → -3x = 12 → x = -4
- x = -2 → f(x) = 6 - 3(-2) = 6 + 6 = 12

✔ Table:
x: -10, -8, -6, -4, -2
f(x): 36, 30, 24, 18, 12

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4) f(x) = x + 4

Given:
x: __, -1, __, 1, __
f(x): 2, __, 4, __, 6

Compute:

- f(x) = 2 → x + 4 = 2 → x = -2
- x = -1 → f(x) = -1 + 4 = 3
- f(x) = 4 → x + 4 = 4 → x = 0
- x = 1 → f(x) = 1 + 4 = 5
- f(x) = 6 → x + 4 = 6 → x = 2

✔ Table:
x: -2, -1, 0, 1, 2
f(x): 2, 3, 4, 5, 6

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5) f(x) = -9 - x

Given:
x: -6, -3, 0, __, 6
f(x): __, __, __, -12, __

Compute:

- x = -6 → f(x) = -9 - (-6) = -9 + 6 = -3
- x = -3 → f(x) = -9 - (-3) = -9 + 3 = -6
- x = 0 → f(x) = -9 - 0 = -9
- f(x) = -12 → -9 - x = -12 → -x = -3 → x = 3
- x = 6 → f(x) = -9 - 6 = -15

✔ Table:
x: -6, -3, 0, 3, 6
f(x): -3, -6, -9, -12, -15

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6) f(x) = -2x + 5

Given:
x: __, __, 3, 4, __
f(x): 5, 3, __, __, -5

Compute:

- f(x) = 5 → -2x + 5 = 5 → -2x = 0 → x = 0
- f(x) = 3 → -2x + 5 = 3 → -2x = -2 → x = 1
- x = 3 → f(x) = -2(3) + 5 = -6 + 5 = -1
- x = 4 → f(x) = -2(4) + 5 = -8 + 5 = -3
- f(x) = -5 → -2x + 5 = -5 → -2x = -10 → x = 5

✔ Table:
x: 0, 1, 3, 4, 5
f(x): 5, 3, -1, -3, -5

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7) f(x) = -4 + 2x

Given:
x: -2, __, __, 1, 3
f(x): __, -6, -4, __, __

Compute:

- x = -2 → f(x) = -4 + 2(-2) = -4 -4 = -8
- f(x) = -6 → -4 + 2x = -6 → 2x = -2 → x = -1
- f(x) = -4 → -4 + 2x = -4 → 2x = 0 → x = 0
- x = 1 → f(x) = -4 + 2(1) = -2
- x = 3 → f(x) = -4 + 6 = 2

✔ Table:
x: -2, -1, 0, 1, 3
f(x): -8, -6, -4, -2, 2

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8) f(x) = 5x

Given:
x: __, -4, __, 2, __
f(x): -25, __, 0, __, 15

Compute:

- f(x) = -25 → 5x = -25 → x = -5
- x = -4 → f(x) = 5(-4) = -20
- f(x) = 0 → 5x = 0 → x = 0
- x = 2 → f(x) = 5(2) = 10
- f(x) = 15 → 5x = 15 → x = 3

✔ Table:
x: -5, -4, 0, 2, 3
f(x): -25, -20, 0, 10, 15

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9) f(x) = 4x - 8

Given:
x: -2, __, 4, __, 8
f(x): __, -8, __, 16, __

Compute:

- x = -2 → f(x) = 4(-2) - 8 = -8 -8 = -16
- f(x) = -8 → 4x - 8 = -8 → 4x = 0 → x = 0
- x = 4 → f(x) = 4(4) - 8 = 16 - 8 = 8
- f(x) = 16 → 4x - 8 = 16 → 4x = 24 → x = 6
- x = 8 → f(x) = 4(8) - 8 = 32 - 8 = 24

✔ Table:
x: -2, 0, 4, 6, 8
f(x): -16, -8, 8, 16, 24

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Final Answer:

All tables completed as follows:

1) x: 1, 2, 3, 4, 5 → f(x): 7, 14, 21, 28, 35
2) x: -4, 4, 8, 12, 16 → f(x): -4, -12, -16, -20, -24
3) x: -10, -8, -6, -4, -2 → f(x): 36, 30, 24, 18, 12
4) x: -2, -1, 0, 1, 2 → f(x): 2, 3, 4, 5, 6
5) x: -6, -3, 0, 3, 6 → f(x): -3, -6, -9, -12, -15
6) x: 0, 1, 3, 4, 5 → f(x): 5, 3, -1, -3, -5
7) x: -2, -1, 0, 1, 3 → f(x): -8, -6, -4, -2, 2
8) x: -5, -4, 0, 2, 3 → f(x): -25, -20, 0, 10, 15
9) x: -2, 0, 4, 6, 8 → f(x): -16, -8, 8, 16, 24