Question

considere as funções f e g tal que f(x)=5-3x e g (x) =7x-8. Calcule o valor de cada expressão a seguir

Answer 1

f(x) = 5-3x e g(x) = 7x-8

a) f(2) - g(2) :

f(2) - g(2) = (5 - 3.2) - (7.2 - 8)

f(2) - g(2) = (5 - 6) - (14 - 8)
f(2) - g(2) = -1 - 6 = -7

b)$\frac{f(5)+g(3)}{f(1).g(8)}$ :

$\frac{f(5)+g(3)}{f(1).g(8)} = \frac{(5-3.5)+(7.3-8)}{(5-3.1).(7.8-8)}$

$\frac{f(5)+g(3)}{f(1).g(8)} = \frac{-10.13}{2.48} = \frac{-130}{96} = - \frac{65}{48}$

c) 7.f(0) + 5.g(1) :

7f(0)+5g(1) = 7.(5 - 3.0) + 5.(7.1 - 8)
7f(0)+5g(1) = 7.5 + 5.(-1) 
7f(0)+5g(1) = 35-5 = 30

d) 2/3 . f(0) - 4g(3) :

2/3.f(0) - 4g(3) = 2/3.(5 - 3.0) - 4.(7.3 - 8)

2/3.f(0) - 4g(3) = 2/3 . 5 - 4.13

2/3.f(0) - 4g(3) = 10/3 - 52 = 10/3 - 52.3/3 = 10-156 / 3 = -146/3