If f(x)= 3x+5 And g(x)=x^2+1 what is the value of g{f(x)}
A) 9x^2+30+26
B) 3x^3+5x^2+3x+5
C) 9x^2+25
D) 3x^2+8
I know it's between b and d
Is it asking for g composition f?

Question

If f(x)= 3x+5 And g(x)=x^2+1 what is the value of g{f(x)} 
A) 9x^2+30+26
B) 3x^3+5x^2+3x+5
C) 9x^2+25
D) 3x^2+8
I know it's between b and d 
Is it asking for g composition f?

dayakar · Answer

f(x)=3x+5---------(1)
g(x)= x^2+1--------(2)

g[f(x)]   = g[ 3x+5]        { from (1)}

dayakar · Answer

replace x with 3x+5 in equation (2)
can u do it

anonymous · Answer

So do I multiply the two together and foil them or do I used the combination process and replace g(x) with f?

dayakar · Answer

just u take equation (2)
both sides u plug in 3x+5 in the place of x do u understand

anonymous · Answer

So it will be (3x+5)^2+1

dayakar · Answer

g(3x+5) = (3x+5)^2 +1 simplify it u can get the answer

anonymous · Answer

Oh ok I understand now

dayakar · Answer

can u show ur work

anonymous · Answer

I got 9x^2+26

dayakar · Answer

(3x)^2+2*3x*5+5^2+1
= 9x^2+30x+25+1
=9x^2+30x+26