Question

Can anyone help?....

Answer 1

Answer:
`fg(x)=4x^3+12x^2-5x-15`

Explanation:

Given:
`f(x)=4x^2-5\text{ and } g(x)=x+3`

We know that for any function f(x) and g(x), the multiplication function (fg) (x) is given by :-

`fg(x)=f(x)g(x)`

Now, for the given functions, we have

`fg(x)=(4x^2-5)(x+3)\\\\\Rightarrow\ fg(x)=4x^2(x+3)-5(x+3)\\\\\Rightarrow\ fg(x)=4x^3+12x^2-5x-15`

Answer 2

The answer two this question is C.

You can get this answer by multiplying the two polynomials and then simplifying. See the steps below:
(4x^2 - 5)(x + 3) ---> Now multiply the two parenthesis.
4x^3 - 5x + 12x^2 - 15 ---> Arrange the numbers by decreasing exponents.
4x^3 + 12x^2 - 5x - 15

No simplifying can be done since there are no like terms.