1.已知1/a-1/b=5,则(2a+3ab-2b)/(a-2b-b)的值是2.若(1-3x)/(x^2-1)=A/(x+1)+B/(x-1),则A= B=3.已知a,b为实数,且ab=1,设M=a/(a+1)+b/(b+1),N=1/(a+1)+1/(b+1)则MN的大小关系

来源：学生作业帮助网 编辑：作业帮 时间：2024/05/06 04:04:16
1.已知1/a-1/b=5,则(2a+3ab-2b)/(a-2b-b)的值是2.若(1-3x)/(x^2-1)=A/(x+1)+B/(x-1),则A= B=3.已知a,b为实数,且ab=1,设M=a/(a+1)+b/(b+1),N=1/(a+1)+1/(b+1)则MN的大小关系

1.已知1/a-1/b=5,则(2a+3ab-2b)/(a-2b-b)的值是2.若(1-3x)/(x^2-1)=A/(x+1)+B/(x-1),则A= B=3.已知a,b为实数,且ab=1,设M=a/(a+1)+b/(b+1),N=1/(a+1)+1/(b+1)则MN的大小关系
1.已知1/a-1/b=5,则(2a+3ab-2b)/(a-2b-b)的值是
2.若(1-3x)/(x^2-1)=A/(x+1)+B/(x-1),则A= B=
3.已知a,b为实数,且ab=1,设M=a/(a+1)+b/(b+1),N=1/(a+1)+1/(b+1)则MN的大小关系

1.已知1/a-1/b=5,则(2a+3ab-2b)/(a-2b-b)的值是2.若(1-3x)/(x^2-1)=A/(x+1)+B/(x-1),则A= B=3.已知a,b为实数,且ab=1,设M=a/(a+1)+b/(b+1),N=1/(a+1)+1/(b+1)则MN的大小关系
1) 1/a-1/b=(b-a)/(ab)=5, a-b=-5ab
(2a+3ab-2b)/(a-2ab-b)=(3ab-2*5ab)/(-5ab-2ab)=1
2) A/(x+1)+B/(x-1)=[A(x-1)+B(x+1)]/(x^2-1)
=[(A+B)x+B-A]/(x^2-1) = (1-3x)/(x^2-1)
所以：A+B=-3, B-A=1,
A=-2, B=-1
3) M=a/(a+1)+b/(b+1)= 1-1/(a+1)+1-1/(b+1）＝2-[1/(a+1)+1/(b+1)]
M-N=2-2[1/(a+1)+1/(b+1)]=2-2(a+1+b+1)/[(a+1)(b+1)]
=2-2(a+b+2)/(ab+a+b+1)
=2-2(a+b+2)/(a+b+2)
=2-2=0
所以M=N

1、原式=2+7ab/(a-2ab-b)
=2+7/(1/b-2-1/a)
=1
2、右边=(Ax+Bx-A+B)/(x^2-1)
由系数对应相等
A+B=-3
B-A=1
得出A=-2,B=-1
3、对MN通分知
M=N

已知3^a+5^b=A,1/a+1/b=2，则A=？ 已知a/b=1/3,则a+b/2a-5b的值为 (1)已知a+b/a-b=3,则5a-5b/3a+3b=________; (2)已知a-b/a+b=2/5,则2a/a+b=________.求结果 已知a-b/a+b=-3,则代数式2(a-b)/a+b-5(a+b)/a-b=? 已知a-b/a+b=-3,则代数式2(a-b)/a+b-5(a+b)/a-b=? 已知a^5+a^4b+a^4+a+b+1=0,且3a+2b=1,则a^2+b^2的值等于 已知3^a+5^b=A,且1/a+1/b=2,求A 已知a,b满足a^3-3a^2+5a=1,b^3-3b^2+5b=5,则a+b=? 已知:a,b满足a^3-3a^2+5a=1,b^3-3b^2+5b=5,则a+b=____. 已知集合A=｛1,4,a²-2a｝,B=｛a-2,a²-4a+2,a²-3a+3,a²-5a｝,若A∩B=｛1,3｝则A∪B=? 已知a-b=4,则2*(b-a)的二次方-3*(a-b)+1 已知A=3A-4B+C,B=5A+4B+2C,求[1]A-B；[2]A+B；[3]2A-3B. 已知ab=1,b-a=3,求ab-a+b的值已知a-b/a+b=3,求代数式2（a-b)/a+b-3(a+b)/5(a-b)的值 已知3^a=5^b=A则1/a+2/b=2则A等于 已知3a=5b=A,且1/a+1/b=2,则A的值? 已知a,b满足a+b=5,a-b=1,求ab,a^2+b^2-3ab 1.已知1/a+1/b=4,则（a-3ab+b)/(2a+2b-7ab)= 已知1/a-1/b=5,则(2a+3ab-2b)/(a-2ab-b)=?