# Math Help - Function helpp

1. ## Function helpp

If f(x) = 3x^3 -2x^2 + x + 7 and g(x) = 2x^2 - 4, find f(2-3i) where i = sqrt(-1).

THANKS

2. Originally Posted by Mr_Green
If f(x) = 3x^3 -2x^2 + x + 7 and g(x) = 2x^2 - 4, find f(2-3i) where i = sqrt(-1).

THANKS
g(x) is not pertinent in this problem.

f(2-3i) = 3*(2 - 3i)^3 - 2*(2 - 3i)^2 + (2 - 3i) + 7

= -138 - 27i + 10 + 24i + 2 - 3i + 7

= -119 - 6i

3. Originally Posted by Mr_Green
If f(x) = 3x^3 -2x^2 + x + 7 and g(x) = 2x^2 - 4, find f(2-3i) where i = sqrt(-1).

THANKS
Are you sure that's the question you're supposed to answer? It's weird that a function g has been specified when it has nothing to do with the problem.

$f(2-3i)=3(2-3i)^3-2(2-3i)^2+(2-3i)+7=\dots$

Now, can you simplify this to the form A+iB where A and B are real numbers?

Edit: I guess I'm too slow.

4. Yes, the g(x) is unecessary. There were multiple questions pertaining to F(x) and g(x). For examole one was g of f(x)..

SOrry the confusion!!