How do you find [g of h](x) if #g(x)=8-2x# and #h(x)=3x#?

1 Answer
Aug 21, 2015

[ g of h ]#(x) = 8-6x#

Explanation:

[g of h]#(x)# can be written as #g(h(x))#

Given #g(color(blue)(x)) = 8 - 2color(blue)(x)#
but the #x# is just a variable place holder and we can replace it with anything we like.

So #g(color(blue)(w)) = 8 - 2color(blue)(w)#
would have identical meanings
as would
#g(color(blue)(h(x))) = 8 -2 color(blue)(h(x)#

Using this last form and replacing color(blue)(h(x)) on the right side with its definition: #color(blue)(h(x)) = color(blue)(3x)#

We have
#g(h(x)) = 8 - 2(color(blue)(3x))#

#color(white)("XXXX")= 8 - 6x#