Răspuns:
Explicație pas cu pas:
E(x)=(x+3-x-1)(x+3+x+1)-x²+9+x²-1
E(x)=2(2x+4)+8
E(x)=4x+8+8
E(x)=4x+16
______
E(x)=(x+1-x+1)(x+1+x-1)+(2x+1-2x+1)(2x+1+2x-1)
E(x)=2·2x+2·4x
E(x)=12x
