化簡:(1)(5ab)/(3c)×(-(12c^2)/(5ab^2))÷3c/a;(2)4/(x-1)-x+1.

化簡:(1)(5ab)/(3c)×(-(12c^2)/(5ab^2))÷3c/a;(2)4/(x-1)-x+1.

(1)(5ab)/(3c)×[-(12c^2)/(5ab^2)]÷3c/a;
=-(5ab)/(3c)×(12c^2)/(5ab^2)×a/3c
=-1/(3c)×(12c^2)/b×a/3c
=-4c/b×a/3c
=-4a/(3b)
(2)4/(x-1)-x+1
=4/(x-1)-(x-1)
=4/(x-1)-(x-1)²;/(x-1)
=[4-(x-1)²;]/(x-1)
=[4-(x²;-2x+1)]/(x-1)
=[4-x²;+2x-1]/(x-1)
=(3-x²;+2x)/(x-1)