If f(x) = 8 - 10x and g(x) = 5x + 4, what is the value of (fg)(-2)?

Solution:

Given:

Functions f(x) = 8 - 10x and g(x) = 5x + 4

To find the value of (fg)(-2),

Let us find the composite function fog(x) for the given functions f(x) and g (x). A function that depends on any other function is called a composite function and f(x) takes all the output values of g(x) as its input.

(fg)(x)= 8 - 10(5x + 4)

= 8 - 50x - 40

(fg)(x) = -50x - 32

To find (fg)(-2)

⇒ (fg)(-2) = -50(-2) - 32

⇒ (fg)(-2) = 100 - 32

⇒ (fg)(-2) = 68

If f(x) = 8 - 10x and g(x) = 5x + 4, what is the value of (fg)(-2)?

Summary:

If f(x) = 8 - 10x and g(x) = 5x + 4, then (fg)(-2) = 68.