Question

几道分式计算题，望高手指点！请写清具体过程，谢谢！

回答快提高悬赏！！！！

Answer 1

1. [(1/x-1 + 1/x+1 -1) (1-x²) +2]÷(x-1)
= [ (2x/x²-1 -1) ×(1-x²)+2]÷(x-1)
=(-2x -1+x² +2)÷(x-1)
=(x-1)²/÷(x-1)
=x-1
2. x-3/3x²-6x ÷( x+2 - 5/x-2)
=x-3/3x(x-2)÷ x²-9/x-2
=x-3/3x(x-2) × x-2/(x+3)(x-3)
=1/3x(x+3)
3. ( a/a+b - b/b-a - 2ab/a²-b² ) ÷ ( 1/a - 1/b )
=( a/a+b + b/a-b - 2ab/a²-b² ) ÷ ( b-a/ab)
= [a(a-b) + b(a+b - 2ab/a²-b² ) )]× ab/b-a
=(a²-2ab+b² /a²-b² )× ab/b-a
=(a-b)²/(a+b)(a-b))× ab/b-a
=-ab/a+b
4. ∵ m² +n²=4mn m>n>0
∴ m² +n²+2mn=(m+n)²=6mn m+n=√6mn
m² +n²-2mn=(m-n)²=2mn m-n=√2mn
m² -n²/mn
=(m+n)(mn)/mn
=√6mn×√2mn/mn
=2√3