Question

Dadas as funções f(x)=2x²-6x-4 e g(x)=-3x²-5x+1 calcule:
a) f(3)
b) f(-2)
c) f(0)
d) f(-0,2)
e) g(1)
f) g(-4)
g) g(0)
g) g(1/2)

Answer 1

f(x) = 2x² - 6x - 4

g(x) = - 3x² - 5x + 1
****************************************
a)
f(x) = 2x² - 6x - 4
f(3) = 2.3² - 6.3 - 4
f(3) = 2.9 - 18 - 4
f(3) = 18 - 18 - 4
f(3) = 0 - 4
f(3) = - 4
****************************************************
b)
f(x) = 2x² - 6x - 4
f(-2) = 2.(-2)² - 6.(-2) - 4
f(-2) = 2.4 + 12 - 4
f(-2) = 8 + 8
f(-2) = 16
*********************************************************
c)
f(x)=2x² - 6x -4 
f(0) = 2.0² - 6.0 - 4
f(0) = 2.0 - 0 - 4
f(0) = 0 - 0 - 4
f(0) = - 4
****************************************************
d) f(- 0,2)
f(x)= 2x² - 6x - 4 

f( - 0,2) = 2.(-0,2)² - 6.(-0,2) - 4
f( - 0,2) = 2. (0,04) + 1,2 - 4
f( - 0,2) = 0,08 + 1,2 - 4
f( - 0,2) = - 2,72
***********************************************
e)
g(x)= - 3x² - 5x +1
g(1) = - 3.1² - 5.1 + 5
g(1) = - 3.1 - 5 + 5
g(1) = - 3 - 5 + 5
g(1) = - 3
**********************************************
f)
g(x) = - 3x² - 5x + 1
g(-4) = - 3. (-4) - 5.(-4) + 1
g( - 4) = 12 + 20 + 1
g( - 4) = 32 + 1
g(-4) = 33  
**********************************************
g)
g(x)=-3x²-5x+1
g(0) = - 3.0² - 5.0 + 1
g(0) = - 3.0 - 0 + 1
g(0) = 0 - 0 + 1
g(0) = 1
*********************************************
h)
g(x) = - 3x² - 5x + 1

g(1/2) = - 3 . 1² - 5.1 + 1
                   2²      2

g(1/2) = - 3 - 5 + 1
              4   2

g(1/2) = - 3 - 10 + 4  
                   4
g (1/2) = - 13 + 4
                  4

g(1/2) = - 9
               4

Answer 2

Resposta:

Explicação passo-a-passo:

As respostas dada pelo especialista na alternativa e) e f) estão erradas o certo seria:

E) g(1)= -3.1²-5.1+1

g(1)= -3.1-5+1

g(1)= -3-5+1

g(1)= -8+1

g(1)= -7

F) g(-4)= -3.(-4)²-5.(-4)+1

g(-4)= -3.16+20+1

g(-4)= -3.16+21

g(-4)= -48+21

g(-4)= -27