Help! I'll fan and medal!
f(x) = 4x + 7, g(x) = 3x2

Find (fg)(x).

Question

Help! I'll fan and medal! 
f(x) = 4x + 7, g(x) = 3x2

Find (fg)(x).

hoothoote · Answer

Answers:
 12x2 + 21x 
 3x2 + 4x + 7
 12x3 + 21x2	
 12x + 21

nnesha · Answer

(fg)(x) is same as f(x) times g(x)

hoothoote · Answer

would it be A or C?

nnesha · Answer

why do you think its A or C ? please post your work :)

nnesha · Answer

$$f(x) \cdot g(x) $$
replace f(x) with (4x+7)
and g(x) = 3x^2 and then distribute parentheses by 3x^2

hoothoote · Answer

Well wouldn't it be 4 times 3? so thats 12x but then I'm confused with the second part and I don't even know if I'm doing it right

hoothoote · Answer

Ohh wait nevermind

nnesha · Answer

well yeah but don't forget there are variables 
it is not just 4 and 4 
4x times 3x^2

hoothoote · Answer

Oh okay so is it A?

hoothoote · Answer

Because the first part would be 12x2

hoothoote · Answer

?

nnesha · Answer

$$\rm g(x) \cdot f(x)  =  3x^2 (4x+2)$$

multiply both terms that are inside the parentheses by 3x^2

nnesha · Answer

remember the exponent rule $$\large\rm x^m \cdot x^n   =x^{m+n}$$
when we multiply same bases we should add their exponents

hoothoote · Answer

So then the exponents together would be 3?

nnesha · Answer

yes correct !

hoothoote · Answer

So the the answer would be C??

nnesha · Answer

yes.

hoothoote · Answer

Thank you!!

nnesha · Answer

np! practice and practice !