Question

Arithmetic of Functions problem.

Answer 1

(f o g)(4) = 45

Explanation:

We have given two functions and we have to find their composition.

f(x) = 4x+1 , g(x) = x²-5

Firstly, we have to find (f o g)(x)

Then, we have to find (f o g)(x).

(f o g)(x) = f(g(x))

Putting the given values of functions in above formula , we have

(f o g)(x) = f(x²-5)

(f o g)(x) = 4(x²-5)+1

simplifying

(f o g)(x) = 4x²-20+1

adding like terms, we have

(f o g)(x) = 4x²-19

Putting x = 4 to above equation , we have

(f o g)(4) = 4(4)²-19

(f o g)(4) = 4(16)-19

(f o g)(4) = 64-19

(f o g)(4) = 45 which is the answer.

Answer 2

(f o g)(4) = 45

Explanation:

f(x)=4x+1

g(x)=x²-5

(f o g)(4)=?

(f o g)(4) = f(g(4))

Calculating g(4):

x=4→g(4)=4²-5

g(4)=16-5

g(4)=11

Replacing g(4)=11

(f o g)(4) = f(g(4))

(f o g)(4) = f(11)

Calculating f(11)

x=11→f(11)=4(11)+1

f(11)=44+1

f(11)=45

Replacing f(11)=45:

(f o g)(4) = f(11)

(f o g)(4) = 45