Question

Given f(x) = x^2 – 3 and g(x) = x+2/x . Find (g ° f)(4).

Answer 1

Answer:

C

Step-by-step explanation:

Given the two functions, we need to find

(g ° f)(4)

This means, we need to put the function f(x) INTO the function g(x) and then evaluate that new function at x = 4.

We put the whole expression of f(x) into "x" of g(x). Shown below:

$f(x)=x^2-3\\g(x)=\frac{x+2}{x}\\(gof)(x)=\frac{x^2-3+2}{x^2-3}\\(gof)(x)=\frac{x^2-1}{x^2-3}$

Now we plug in 4 into x and evaluate:

$(gof)(x)=\frac{x^2-1}{x^2-3}\\(gof)(4)=\frac{4^2-1}{4^2-3}\\(gof)(4)=\frac{15}{13}$

Thus,

correct answer is C