What ia the value of f(a) if f(x)=3x-2?

1 Answer
Jun 26, 2018

#f(a)=3a-2#

Explanation:

If #f(color(red)x)=3color(red)x-2#
then
#color(white)("XXX")f(color(blue)a)#
is simply #f(color(red)x)# with #color(red)x# replaced by #color(blue)a#

#color(white)("XXX")f(cancel(color(red)x)^color(blue)a)=3cancel(color(red)x)^color(blue)a-2#
#color(white)("XXXXXXX")=3color(blue)a-2#

For a more concrete example, you might evaluate #f(color(magenta)6)# for the same definition of #f(color(red)x)#
#color(white)("XXX")f(cancel(color(red)x)^color(magenta)6)=3 * cancel(color(red)x)^color(magenta)6-2#

#color(white)("XXX")f(color(magenta)6)=3 * color(magenta)6-2=18-2=16#