If #f(x) = -6x - 3#, then how do you find f(2)?

2 Answers
Gió
Jul 2, 2015

#f(2)=-15#

Explanation:

Substitute #2# instead of #x# into your function so you get:
#f(2)=(-6*2)-3=-12- 3=-15#

Jim H
Jul 2, 2015

Replace every #x# with #2# and do the arithemetic.

Explanation:

In the definition of this function the variable #x# is a name for the blank space. (Definition for the rest of this one problem, not for other problems too.)

#fcolor(red)((x)) = -6 color(red)((x)) -3#

To find #f(2)#, replace all of the #x#'swith #2# and do the arithmetic.

#fcolor(red)((2)) = -6 color(red)((2)) -3#

Now we do the arithmetic:

#f(2) = -6(2) -3 = -12 - 3 = -15#

Here's another example: for the same #f#, find #f(-5)#

Solution:
#fcolor(red)((-5)) = -6 color(red)((-5)) -3#

# = 30-3#
# = 27#

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