Question

f(x)=-3x+9,sa se calculeze f(1)+f(2)+f(-1)+f(-2)??Ajutatima rapid

Answer 1

f(1)=-3×1+9
f(2)=-3×2+9
f(-1)=-3×(-1)+9
f(-2)=-3×(-2)+9

f(1)+f(2)+f(-1)+f(-2)=
=(-3)×1+9+(-3)×2+9+(-3)×(-1)+9+(-3)×(-2)
+9
=-3[1+2+(-1)+(-2)]+9×4
=-3(3-3)+36
=-3×0+36
=0+36
=36