Question

dada a função f(x) 4x-8, determinar f(-3), f(0) e f(2)

Answer 1

f(x) = 4x-8
f(-3) = 4.(-3)-8
f(-3) = (-12)-8
f(-3) = -20

f(0) = 4.0-8
f(0) = 0-8
f(0) = -8

f(2) = 4.2-8
f(2) = 8-8
f(2) = 0

Answer 2

Basta vc substituir o x por -3, 0 e 2: 
f(-3)= 4(-3) -8
f(-3)= -20

f(0) = 4(0) -8 
f(0)= -8

f(2) = 4(2) -8
f(2) = 8-8 = 0