bài 1: rút gọn các biểu thúc sau
a, \(\frac{\sqrt{1-2x+x^2}}{x-1}\)
b, \(\frac{\sqrt{\left(x-3\right)^2}}{3-x}\)
c, \(\frac{\sqrt{9x^2-6x+1}}{9x^2-1}\)
d, 4-x-\(\sqrt{4-4x+x^2}\)
bài 2 rút gọn
a, \(\frac{\sqrt{6}+\sqrt{10}}{\sqrt{21}+\sqrt{35}}\)
b, \(\frac{\sqrt{405+3\sqrt{27}}}{3\sqrt{3}+\sqrt{45}}\)
c, \(\frac{\sqrt{2}+\sqrt{3}+\sqrt{4}-\sqrt{6}-\sqrt{9}-\sqrt{12}}{\sqrt{2}+\sqrt{3}+\sqrt{4}}\)
d, \(\frac{\sqrt{6-2\sqrt{5}}}{\sqrt{5}-1}\)