Question

Função f(x)=x2-4x+8
Dada a função f(x), determine:
A) f(2)
B) f(5)
C) f(-2)+f(0)
D) f(3)×f(4)
E) f(2,3)

Answer 1

a) f(2) = 2² -4.2 + 8
    f(2) = 4 -8 + 8 
    f(2) = 4 
 
b) f(5) = 5² - 4.5 + 8
    f(5) = 25 - 20 + 8
    f(5) = 12

c) f(-2) = (-2)² -4.(-2) + 8 --- f(0) = 0² -4.0 + 8
    f(-2) = 4 + 8 + 8 ----------- f(0) = 0 - 0 + 8
    f(-2) = 20 -------------------- f(0) = 8
    f(-2) + f(0) = 28

d) f(3) = 3² -4.3 +8 + f(4) = 4² -4.4 + 8
    f(3) = 9 -12 + 8 --- f(4) = 16 - 16 + 8
    f(3) = 5 ------------- f(4) = 8
    f(3) × f(4) = 40

e) f(2,3) = 2,3² -4.2,3 + 8
    f(2,3) = 5,29 - 9,2 + 8
    f(2,3) = 4,09