Andrew M. answered • 03/20/17
Tutor
New to Wyzant
Mathematics - Algebra a Specialty / F.I.T. Grad - B.S. w/Honors
Is this f(x)g(x) or f(g(x))? It looks like you
are multiplying functions.
Let's let y = f(x) for ease of presentation
fg(x) = 2x+3
g(x) = 4/x
y(4/x) = 2x + 3
y = (2x+3)(x/4)
y = (2x2 + 3x)/4
f(x) = (2x2+3x)/4
Check: f(x)g(x) = [(2x2+3x)/4](4/x) = 2x + 3
Andrew M.
g(x) = 4/x
f(g(x)) = 2x + 3
f(4/x) = 2(4/x) + 3 = 8/x + 3
f(x) = 8/x + 3
Check: f(4/x) = 8/(4/x) + 3
= 8x/4 + 3
= 2x + 3
Report
03/20/17
Daniel K.
Wait how did you get f(4/x) = 2(4/x) + 3 = 8/x + 3?
f(4/x)=2x+3
Report
03/20/17
Andrew M.
g(x) = 4/x
Thus f(g(x)) = f(4/x)
We want f(4/x) = 2x + 3
Whatever we have in the parenthesis
part of f(x) we put in place of x.
Report
03/20/17
Daniel K.
03/20/17