What is the range if f(x) = 3x - 9 and domain: -4,-3,0,1,8?

2 Answers
Jim G.
Jul 24, 2018

y in{-21,-18,-9,-6,15}y∈{−21,−18,−9,−6,15}

Explanation:

"to obtain the range substitute the given values in the "to obtain the range substitute the given values in the
"domain into "f(x)domain into f(x)

f(-4)=-12-9=-21f(−4)=−12−9=−21

f(-3)=-9-9=-18f(−3)=−9−9=−18

f(0)=-9f(0)=−9

f(1)=3-9=-6f(1)=3−9=−6

f(8)=24-9=15f(8)=24−9=15

"range is "y in{-21,-18,-9,-6,15}range is y∈{−21,−18,−9,−6,15}

Alan N.
Jul 24, 2018

Range = {-21, -18, -9, -6, +15}{−21,−18,−9,−6,+15}

Explanation:

Here we have a lineal function f(x) = 3x-9f(x)=3x−9 defined for x={-4,-3,0,1,8}x={−4,−3,0,1,8}

The slope of f(x)=3 -> f(x)f(x)=3→f(x) is linear increasing.

Since f(x)f(x) is linear increasing, its minimum and maximum values will be at the minimum and maximum values in its domain.

:. f_min = f(-4) = -21

and f_max = f(8) = 15

The other values of f(x) are:

f(-3) = -18
f(0) = -9
f(1) = -6

Hence the range of f(x) is {-21, -18, -9, -6, +15}

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