Question

Seja f: R - R a união definida por f(x) = -3x + 3. Determine o valor de f(1) - f(-2) + f(3).

Answer 1

f(1)=-3.1+3
f(1)=-3+3
f(1)=0

f(-2)=-3.(-2)+3
f(-2)=6+3
f(-2)=9

f(-3)=-3.3+3
f(3)=-9+3
f(3)=-6

f(1)-f(-2)+f(3)
0-9+(-6)
-9-6
-15

Answer 2

 f(x) = - 3x + 3

 f(1) - f(-2) + f(3) = 0 - 9 - 6 ==> 3 


f(1) =  - 3(1) + 3 = - 3 + 3 = 0
f(-2) =  - 3(-2) + 3= 6 + 3 = 9
f(3) =  - 3(3) + 3 = - 9 + 3 = - 6