Question

Let f(x) = -4x - 2 and g(x) = 5x - 6. Find fxg and state its domain.

a. 8x^2 + 34x - 30; all real numbers except x = 1
b. -20x^2 + 14x + 12; all real numbers except x = 6
c.-20x^2 + 14x + 12; all real numbers
d.8x^2 + 34x - 30; all real numbers

Answer 1

c) -20x^2+14x+12

all real numbers

Explanation:

So (fg)(x)=f(x)g(x)=(-4x-2)(5x-6).

Need find the expression in standard form we need to use foil:

First: (-4x)(5x)=-20x^2

Outer: (-4x)(-6)=24x

Inner: (-2)(5x)=-10x

Last: (-2)(-6)=12

--------------------------Add like terms:

-20x^2+14x+12

Polynomials have domain all real numbers.

There are no restrictions on what x can be. For every number you plug in, you will get a number back.

Answer 2

c.-20x^2 + 14x + 12; all real numbers

Explanation:

f(x) = -4x - 2

g(x) = 5x - 6

Therefore, -20x^2 + 14x + 12; all real numbers.