Question

Se considere E(x)=(1+x)(1-x)+(x+2)²-2(x+2),unde x este nr real. Determinati nr real a pt care E(a)=-1

Answer 1

E(x)= 1-x²  +  x²+4x+4  -  2x-4   dupa restringerea termenilor asemenea , obtinem:
E(x)=2x +1 ;
pt. x = a  ⇒  E(a)=-1  adica: 2a+1=-1  ⇒  2a=-2  deci  a=-1

Answer 2

[tex]E(x)=(1+x)(1-x)+(x+2)^2-2(x+2) \\ E(x)=1-x^2+x^2+4+4x-2x-4 \\ E(x)=2x+1 \\ 2a+1=-1 \\ 2a=-2 \\ \boxed{a=-1}[/tex]