Question

for f(x)=7x and g(x)=x+1, find the following functions. a.(fog)(x); b.(gof)(x); c.(fog)(4); d.(gof)(4)

Answer 1

`a.(fog)(x) = 7x + 7 \\ b.(gof)(x) = 7x + 1 \\ c.(fog)(4) = 35 \\ d.(gof)(4) = 29`

Explanation:

Greetings !

a. (fog)(x)= f[g(x)] = 7(x+1)

• (fog)(x)= 7x+7

b. (gof)(x) = g[f(x)] =7x+1

c. (fog)(4)=7(4)+7=28+7=35

d. (gof)(4)= 7(4)+1=28+1=29

Answer 2

• f(x)=7x
• g(x)=x+1

(fog)(x)

• f(g(x))
• f(x+1)
• 7x+7

(gof)(x)

• g(f(x))
• g(7x)
• 7x+1

(fog)(4)

• 7(4)+7
• 35

(gof)(4)

• 7(4)+1
• 29