Rút gọn biểu thức ( cần gấp ạaa)

`A=(1/(\sqrt{x}-1)-1/(\sqrt{x}))÷((\sqrt{x}+1)/(\sqrt{x}-2)-(\sqrt{x}-3)/(\sqrt{x}-1)) (đk:x\ne1;x\ne0;x\ne4;x>0)`

`A=(\sqrt{x}-\sqrt{x}+1)/(\sqrt{x}(\sqrt{x}-1))÷((\sqrt{x}+1)(\sqrt{x}-1)-(\sqrt{x}-3)(\sqrt{x}-2))/((\sqrt{x}-2)(\sqrt{x}-1))`

`A=1/(\sqrt{x}(\sqrt{x}-1))÷(x-1-(x-2\sqrt{x}-3\sqrt{x}+6))/((\sqrt{x}-2)(\sqrt{x}-1))`

`A=1/(\sqrt{x}(\sqrt{x}-1))÷(x-1-x+5\sqrt{x}-6)/((\sqrt{x}-2)(\sqrt{x}-1))`

`A=1/(\sqrt{x}(\sqrt{x}-1))·((\sqrt{x}-2)(\sqrt{x}-1))/(5\sqrt{x}-7)`

`A=(\sqrt{x}-2)/(\sqrt{x}(5\sqrt{x}-7))`

`A=(\sqrt{x}-2)/(5x-7\sqrt{x})`

`B=(12/(\sqrt{5}+1)-4/(\sqrt{5}+2)+20/(3+\sqrt{5}))·(10+3\sqrt{5})`

`B=[(12(\sqrt{5}-1))/((\sqrt{5}+1)(\sqrt{5}-1))-(4(\sqrt{5}-2))/((\sqrt{5}+2)(\sqrt{5}-2))+(20(3-\sqrt{5}))/((3+\sqrt{5})(3-\sqrt{5}))]·(10+3\sqrt{5})`

`B=[(12(\sqrt{5}-1))/(5-1)-(4(\sqrt{5}-2))/(5-4)+(20(3-\sqrt{5}))/(9-5)]·(10+3\sqrt{5})`

`B=[(12(\sqrt{5}-1))/4-(4(\sqrt{5}-2))/1+(20(3-\sqrt{5}))/4]·(10+3\sqrt{5})`

`B=[3(\sqrt{5}-1)-4(\sqrt{5}-2)+5(3-\sqrt{5})]·(10+3\sqrt{5})`

`B=(3\sqrt{5}-3-4\sqrt{5}+8+15-5\sqrt{5})·(10+3\sqrt{5})`

`B=(20-6\sqrt{5})·(10+3\sqrt{5})`

`B=2(10-3\sqrt{5})(10+3\sqrt{5})`

`B=2(100-45)`

`B=2·55`

`B=110`