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Let f(x)=4x+1 and g(x)=3/4. evaluate each expression symbolically.

a) (f+g)(4)

b) (f-g)(1/4)

c) (fg)(5)

d) (f/g)(0)​

1 Answer

4 votes

Answer:

a. 20 b. 1 13/16 c. 78 3/4 d. undefined

Explanation:

since f(x)=4x+1 and g(x)=3x/4

a) (f+g)(4)

= f(4) + g(4)

f(4) = 4(4)+1 = 17

g(4) = 3(4)/4 = 3

therefore

(f+g)(4) = 17 + 3 = 20

b) (f-g)(1/4)

= f(1/4) - g(1/4)

f(1/4) = 4(1/4)+1 = 2

g(1/4) = 3(1/4)/4 = 3/16

therefore

(f-g)(1/4) = 2 - 3/16 = 29/16 = 1 13/16

c) (fg)(5)

= f(5) x g(5)

f(5) = 4(5)+1 = 21

g(5) = 3(5)/4 = 15/4

therefore

(fg)(5) = 21 x 15/4 = 315/4 = 78 3/4

d) (f/g)(0)​

= f(0) / g(0)

f(0) = 4(0)+1 = 1

g(0) = 3(0)/4 = 0

therefore

(f/g)(0)​ = 1 / 0 = undefined

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