đừng tin 

\(\left(\dfrac{1}{2}xy\right)^3.\left(\dfrac{2}{3}yt\right)^2.\left(-xy\right)\\ =\dfrac{1}{8}x^3y^3.\dfrac{4}{9}y^2t^2.\left(-1\right)xy\\ =\left[\dfrac{1}{8}.\dfrac{4}{9}.\left(-1\right)\right]\left(x^3.x\right)\left(y^3.y^2.y\right).t^2\\ =-\dfrac{1}{18}x^4y^6t^2\)

là ny chẳng xen vào đc à

\(\dfrac{-5}{-15}+\dfrac{9}{7}+\dfrac{1}{-3}-\dfrac{-276}{14}\\ =\dfrac{1}{3}+\dfrac{9}{7}-\dfrac{1}{3}+\dfrac{138}{7}\\ =\left(\dfrac{1}{3}-\dfrac{1}{3}\right)+\left(\dfrac{9}{7}+\dfrac{138}{7}\right)\\ =0+\dfrac{147}{7}\\ =21\)

\(\dfrac{3}{1.4}+\dfrac{3}{4.7}+...+\dfrac{3}{100.103}\\ =1-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{7}+...+\dfrac{1}{100}-\dfrac{1}{103}\\ =1-\dfrac{1}{103}\\ =\dfrac{102}{103}\)

kệ mọe con Mai đi e 

sao là sao?

đừng tin con Mai lợn

chữ vẫn đọc được mà