- max笔记
-
a+b b-c
(1) —— - ——
ab bc
c(a+b) a(b-c)
= ———— - ———
abc abc
ac+bc-ab+ac
= ——————
abc
2ac+bc-ab
= —————
abc
x-3 2
(2) ——— - ———
x²-1 1+x
x-3 2
= ————— - ———
(x+1)(x-1) x+1
x-3 2(x-1)
= ————— - —————
(x+1)(x-1) (x+1)(x-1)
x-3-2x+2
= —————
(x+1)(x-1)
-x-1
= —————
(x+1)(x-1)
-1
= ——
x+1
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- 大鱼炖火锅
-
(a+b)/ab+(b+c)/bc
=c(a+b)/abc+a(b+c)/abc
=(ac+bc+ab+ac)/abc
=(ab+bc+2ac)/abc
(x-3)/(x²-1)-2/(1+x)
=(x-3)/(x²-1)-2(x-1)/(x²-1)
=(x-3-2x+2)/(x²-1)
=(-x-1)/(x+1)(x-1)
=-1/(x-1)
=1/(1-x)