\(cot33^o+sin^225-tan57^o+sin^265^o-\dfrac{5tan24^o}{cot66^o}\)

\(\dfrac{sin27^o}{cos27^o}-7sin^265^o-7sin^225^o-tan27^o+tan45^o\)

\(sin^256^o-cot27^o+sin^234^o+tan63^o-12.tan37^o.tan53^o\)

giải và biện luận theo m

\(\left\{{}\begin{matrix}mx-y=2m\\4x-my=m+6\end{matrix}\right.\)

`(1/(\sqrt{x}+3) + 1/(x\sqrt{x}-9\sqrt{x})) : ((\sqrt{x})/(\sqrt{x}+3) - (3\sqrt{x}-3)/(x+3\sqrt{x}))`

rút gọn

`((9-3x)/(x^2 +4x-5) - (x+5)/(1-x) - (x+1)/(x+5)) : (7x-14)/(x^2 -1)`