计算下列各式;①(12xy/5a)/(6x^2y),②(2x^2/3y^2)*5y/6x)/(10y/21x^2),③(a^2-1/a^2+4a+4)/(a+1/a+2),④(a+2/a^2-2a)*(a^2-4a+4/a+2),⑤(x-2/x^2-1)/(x+1/x^2+2x+1) ,⑥[(2x/x-2)-(x/x+2)]/(x/x^2-40,⑦(1/a-1)-1-a,⑧[(x-2/x+2)-(x+2/x-2)]*(x^2-2x/x^2)⑨[(x+2/x^2-2x)-(x-1/x^2-4x+4)]/(x-4/x)⑥[(2x/x-2)-(x/x+2)]/(x/(x^2-4)

问题描述:

计算下列各式;①(12xy/5a)/(6x^2y),②(2x^2/3y^2)*5y/6x)/(10y/21x^2),
③(a^2-1/a^2+4a+4)/(a+1/a+2),④(a+2/a^2-2a)*(a^2-4a+4/a+2),⑤(x-2/x^2-1)/(x+1/x^2+2x+1) ,⑥[(2x/x-2)-(x/x+2)]/(x/x^2-40,⑦(1/a-1)-1-a,⑧[(x-2/x+2)-(x+2/x-2)]*(x^2-2x/x^2)⑨[(x+2/x^2-2x)-(x-1/x^2-4x+4)]/(x-4/x)
⑥[(2x/x-2)-(x/x+2)]/(x/(x^2-4)

①(12xy/5a)/(6x^2y)=(12xy/5a)*(1/6x^2y)=12/30ax=2/5ax.②(2x^2/3y^2)*5y/6x)/(10y/21x^2)=(5/9y)*(21x^2/10y)=7x^4/6y^2.③(a^2-1/a^2+4a+4)/(a+1/a+2)=*<(a+2)/(a+1)>=(a-1)/(a+2).④(a+2/a^2-2a)*(a^2-4a+4...