SOLUTION: If f(x)=3x-1, find (f(x+h)-f(x))/h My guess is that I have to foil the equation to cancel out like terms?

Algebra ->  Functions -> SOLUTION: If f(x)=3x-1, find (f(x+h)-f(x))/h My guess is that I have to foil the equation to cancel out like terms?      Log On


   

Question 853990: If f(x)=3x-1, find (f(x+h)-f(x))/h
My guess is that I have to foil the equation to cancel out like terms?
Found 2 solutions by josgarithmetic, josmiceli:
Answer by josgarithmetic(39623) About Me  (Show Source):
You can put this solution on YOUR website!
Guess not!
f(x)=3x-1.
f(x+h)=3(x+h)-1=3x+3h-1.

Replace them into the expression.

%283x%2B3h-1-%283x-1%29%29%2Fh
%283h-1%2B1%29%2Fh
3h%2Fh
highlight%283%29.

Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Just substitute +x+%2B+h+ for +x+ in the 1st
function everywhere you see +x+, then
do the required algebra
------------------------
given:
+f%28x%29+=+3x+-+1+
find:
+%28+f%28+x%2Bh+%29+-+f%28+h+%29+%29+%2F+h+
+%28+3%2A%28+x%2Bh+%29+-+1+-+%28+3x+-+1+%29+%29+%2F+h+
+%28+3x+%2B+3h+-+1+-+3x+%2B+1+%29+%2F+h+
+%28+3x+%29%2Fh+%2B+3+-+1%2Fh+-+%283x+%29%2Fh+%2B+1%2Fh+
+%28%28+3x+%29%2Fh+-+%28+3x+%29%2Fh%29+%2B+%281%2Fh+-+1%2Fh%29+%2B+3+=+3+