1
2*(3x+1)+3*(2x-3)=6x+2+6x-9=12x-7
2
[1(√x+1)-x*1/√x]/(√x+1)²+[1*(√x-1)-x*1/2√x]/(√x-1)²=
=(√x+1-√x)/(√x+1)²+(√x-1-√x)/(√x-1)²=1/(√x+1)²-1/(√x-1)²=
(x-2√x+1-x-2√x-1)/(x-1)²=-4√x/(x-1)²
3
[3/2√x*(2+√x)-3√x*1/2√x]/(2+√x)²=(6+3√x-3√x)/[2√x(2+√x)²]=3/[√x(2+√x)²]