1/a+1/b=6,那么a+12ab+b分之a-3ab+b的值为?

1.

1/a+1/b=6
(a+b)/(ab)=6
a+b=6ab

(a-3ab+b)/(a+12ab+b)
=(6ab-3ab)/(6ab+12ab)
=3/18
=1/6

2.

1/a-1/b=5
(b-a)/(ab)=5
a-b=-5ab
(2a+3ab-2b)/(a-2ab-b)
=(-5ab*2+3ab)/(-5ab-2ab)
=(-7)/(-7)
=1

a-3ab+b 1/b-3+1/a
________=___________=1/6
a+12ab+b 1/b+12+1/a

另外一题用类似的方法 答案为 1

1/a+1/b=6,
a+b=6ab
(6ab-3ab0/(6ab+12ab)=1/6

1/a-1/b=5
b-a=6ab
(-2(b-a)-3ab)/(-(b-a+2ab))
=12ab/8ab
=3/2

由1/a+1/b=6得a+b=6ab,则a+12ab+b=18ab,a-3ab+b=3ab,所以答案为6.