If f(x) = 5x^2 − 4 and g(x) = x − 2, what is (f*g)(-3)?

Question

If f(x) = 5x^2 − 4 and  g(x) = x − 2, what is (f*g)(-3)?

zachcrat · Answer

HANDWRITTEN TIME fOR ME, I'M ON IT

tkhunny · Answer

This is only an exercise in understanding the notation.

Can you find g(-3)?

zachcrat · Answer

25 is ur answer, sorry about earlier, caps lock was on

love_to_love_you · Answer

25 isn't an option and yeah give me a sec tkhunny

love_to_love_you · Answer

-5?

tkhunny · Answer

Perfect.  Now, just to be VERY CLEAR, which one of these is what your problem statemetn says?

fºg
f*g

It's a circle (iteration) or a star (means multiplication).

love_to_love_you · Answer

circle

tkhunny · Answer

Okay, this means you take the value from g(-3), which is -5, and put that into f.

g(-3) = -5
Find f(-5).

love_to_love_you · Answer

121?

tkhunny · Answer

That's what I get.

It may also be written f(g(-3))  This is the same thing.

love_to_love_you · Answer

so that's the answer?

tkhunny · Answer

Did we do what was asked?  Yes.  We're done.

love_to_love_you · Answer

Thank you!

triciaal · Answer

do you have another question about this process?