Question

Ajutati-ma urgenttt ! 
va rog frumoss ! 

Answer 1

42) E(x)=[(x-3)(x-3)-x(x-3)+x·x)]/x(x-3)·[2x/(2x²-6x+18)]=simplif cu x=
           =(x²-6x+9-x²+3x+x²)/(x-3)·[2/2(x²-3x+9)]=
          =(x²-3x+9)/(x-3)·1/(x²-3x+9)=1/x-3
b)( 1/x-3)<0
x-3∈D1
x-3=1⇒x=4>0

c)E(a)=1/a-3
a-3∈D1
a-3=1
a=4
a∈{4}

43) a) x²+x-2=(x-1)(x+2)
x²+x-2=x²+2x-x-2
x²+x-2=x²+x-2
b) E(x)=[3(x+2)/(x-1)(x+2)-2/(x+1)+4x/(x+1)(x-1)]·x-1=
          =[3/(x-1)-2/(x+1)+4x/(x+1)(x-1)]·x-1=
          =[3(x+1)-2(x-1)+4x]/(x+1)=
           =(3x+3-2x+2+4x)/(x+1)=
          =(5x+5)/(x+1)=5(x+1)/(x+1)=5