Question

E(x)=7(x+2)/x-3 calculati
a) A= x apartine de Z/-5,-2,-2,1,3 unde E(x) apartine de Z

Answer 1

E(x)=7(x+2)/(x-3)=(7x+14)/(x-3)=(7x-21+35)/(x-3)=
=(7x-21)/(x-3) +35/(x-3)=7(x-3)/(x-3) +35/(x-3)=7 +35/(x-3)
E(x) apartine Z, rezulta:
35/(x-3) apartine Z, deci x-3 divide 35
x-3={-35,-7,-5,-1,+1,+5,+7,+35}
x={-32, -4,-2,+2,+4,+8,+10,+38}
Din enunt x este diferit de -2,
x={-32, -4,+2,+4,+8,+10,+38}