Question

Dada a função f(x)=2x - 6x + 8 calcule f(1) - f(2)

Answer 1

f(x) = 2x - 6x + 8
f(1)  = 2 · 1 - 6 · 1 + 8
f(1) = 2 - 6 + 8
f(1) = 4


f(x) = 2x - 6x + 8
f(2) = 2 · 2 - 6 ·2 + 8
f(2) = 4 - 12 + 8
f(2) = 4 - 4
f(2) = 0

Answer 2

f(x) = 2x-6x+8

f(1) = 2.1 - 6.1 + 8
f(1) = 2 - 6 + 8
f(1) = 4

f(2) = 2.2 - 6.2 + 8
f(2) = 4 - 12 +8
f(2) = 0

f(1) - f(2)
 4    -  0 = 4
Portanto f(1) - f(2) dá 4