1/(x+1)÷x-2*(x²+3x+2)/(x²-4)=1/(x+1)*1/(x-2)*(x+1)(x+2)/[(x-2)(x+2)]=1/(x-2)² [(a-b)/a²b]²÷([(a-b)/a]³*[ab²/(a²-b²)]=(a-b)²/a^4b²×a³/(a-b)³×ab²/(a-b)(a+b)=1/[(a+b)(a-b)²]
