lamatematica urgent.

Răspuns:
a)x= -2
f(-2)= -2×2+4/-2=-4+4/-2=0/-2=0
b)×= -0,4= -4/10= -2/5
f(-2/5)= 2×(-2/5)+4/-2/5= -4/5+20/5 totul pe -2/5=16/5 /-2/5= -8
c)x= -4
f(-4)= 2×(-4)+4/-4= -8+4/4= -4/4 =-1