calculați: f(1) + f (2)+...+ f(6).
![Calculați F1 F 2 F6 class=](https://ro-static.z-dn.net/files/d10/4e71840b00f700a0a63c5b1598df0399.jpg)
f(1)= -2×1+4=-2+4=2
f(2)=-2×2+4=-4+4=0
f(3)=-2×3+4=-6+4=-2
f(4)=-2×4+4=-8+4=-4
f(5)=-2×5+4=-10+4=-6
f(6)=-2×6+4=-12+4=-8
2+0+(-2)+(-4)+(-6)+(-8)=
2-2-4-6-8=
0-4-6-8=
-10-8=
-18