a)(2x+1)/(x-2)+(1-2x)/(x+2) +(x²+16)/(x²-4)=
[(2x+1)(x+2)+(1-2x)(x-2)+(x²+4)]/(x²-4)=
(2x²+2x+x+2+x-2-2x²+4x+x²+4)/(x²-4)=(x²+8x+4)/(x²-4)
b)(x-2)/(x+1)+ (x+3)/(x+2) + (5-x²) /(x²+3x+2)=
[(x-2)(x+2)+(x+3)(x+1)+5-x²]/(x²+3x+2)=
(x²+2x-2x-4+x²+3x+x+1+5-x²)/(x²+3x+2)=
=(x²+4x+2)/(x²+3x+2)
c)(7x-1)/(2x²+6x) -( 3x-5)/(x²-9)+ (9x-3)/(2x³-18x)=
(7x-1)/2x(x+3)-(3x-5)/(x+3)(x-3)+(9x-3)/2x(x+3)(x-3)=
[(7x-1)(x-3)-2x(3x-5)+9x-3]/(2x(x+3)(x-3)=
(7x²-21x-x+3-6x²+10x+9x-3)/2x(x-3)(x+3)=
(x²-3x)/2x(x+3)(x-3)=x(x-3)/2x(x+3)(x-3)=1/2(x+3)
e)(x²-27) /(x²-9 )- [5/(x+3) -x /(x-3) -( x+1)/(x-3)]=
(x²-9)/(x-3)(x+3)-[5(x-3)-x(x+3)-(x+1)(x+3)]/(x-3)(x+3)=
(x²-9-5x+15x+x²+3x+x²+3x+x+3)/(x-3)(x+3)=
(3x²+17x-6)/x²-9