Question

Dada a função f(x) = 2x³ - 4x +2, calcule f(1) - f(3).

Answer 1

f(x) = 2x³ - 4x + 2 

f(1) = 2.1³ - 4.1 + 2 
         2.1 - 4 + 2
         2 - 4 + 2
        0

f(3) = 2.3³ - 4.3 + 2
         2.27 - 12 + 2
         54 - 12 + 2
         44

f(1) - f(3)
0 - 44
-44

Answer 2

f(1) = 2(1)³ - 4(1) + 2
f(1) = 2(1) - 4 + 2
f(1) = 2 - 4 + 2
f(1) = 0

f(3) = 2(3)³ - 4(3) + 2
f(3) = 2(27) - 12 + 2
f(3) = 54 - 12 + 2
f(3) = 44

f(1) - f(3) = (0) - (44)
f(1) - f(3) = -44