Question

If f(x) = 4x + 5 and fog(x) = 8x + 13 then find g(x).​

Answer 1

given

f(x).4x+5

fog(x).8x+13

now

fog(x):8x+13

4x+5(g(x)):: 8x+13

g(x):: 8x+13/4x+5

Answer 2

g(x) = 2x + 2

Explanation:

One is given the following information:

• f(x) = 4x + 5
• f o g (x) = 8x + 13

One is asked to find the following:

• g(x)

Remember, (f o g (x)) is another way of representing a composite function. A more visual way of representing this composite function is the following (f(g(x)). In essence, one substitutes the function (g(x)) into the function (f(x)) in places of the varaible (x). Thus, represent this in the form of an equation:

f(g(x)) = 8x + 13

Substitute the given infromation into the equation:

4(g(x)) + 5 = 8x + 13

Solve for (g(x)) in terms of (x). Remember to treat (g(x)) as a single parameter:

4(g(x)) + 5 = 8x + 13

Inverse operations,

4(g(x)) + 5 = 8x + 13

4(g(x)) = 8x + 8

g(x) = (8x + 8) ÷ 4

g(x) = 2x + 2