Giải giùm mk với @@@@

\(\frac{\frac{3}{4}-\frac{3}{5}+\frac{3}{7}+\frac{3}{11}}{\frac{13}{4}-\frac{13}{5}+\frac{13}{7}+\frac{13}{11}}=\frac{3\left(\frac{1}{4}-\frac{1}{5}+\frac{1}{7}+\frac{1}{11}\right)}{13\left(\frac{1}{4}-\frac{1}{5}+\frac{1}{7}+\frac{1}{11}\right)}=\frac{3}{13}\)

\(\frac{3}{7}\left(\frac{7}{13}-\frac{3}{7}\right)-\frac{7}{13}\left(-\frac{3}{7}+\frac{26}{49}\right)\)

\(=\frac{3}{7}\left(\frac{49}{91}-\frac{39}{91}\right)-\frac{7}{13}\left(-\frac{21}{49}+\frac{26}{49}\right)\)

\(=\frac{3}{7}.\frac{10}{91}-\frac{7}{13}.\frac{5}{49}\)

\(=\frac{30}{637}-\frac{5}{91}=\frac{30}{637}-\frac{35}{637}=\frac{-5}{637}\)

tính theo công thức bạn nhé

a, A = ( 1/3 + 12/67 + 13/41 ) - ( 79/67 - 28/41 )

A = (\(\frac13\) + \(\frac{12}{67}\) + \(\frac{13}{41}\)) - (\(\frac{79}{67}\) - \(\frac{28}{41}\))

A = \(\frac13\) + \(\frac{12}{67}\) + \(\frac{13}{41}\) - \(\frac{79}{67}\) + \(\frac{28}{41}\)

A = - (\(\frac{79}{67}-\frac{12}{67}\)) + (\(\frac{13}{41}\) + \(\frac{28}{41}\))

A = - 1 + 1 + \(\frac13\)

A = 0 + \(\frac13\)

A = \(\frac13\)

b, B = 3/4×7 + 3/7×10 + 3/10×13 + ......+ 3/73×76

B = \(\frac{3}{4\times7}\) + \(\frac{3}{7\times10}\) + \(\frac{3}{10\times13}\) + ... + \(\frac{3}{73\times76}\)

B = \(\frac14-\frac17\) + \(\frac17-\frac{1}{10}\) + ... + \(\frac{1}{73}-\frac{1}{76}\)

B = \(\frac14\) - \(\frac{1}{76}\)

B = \(\frac{19}{76}-\) \(\frac{1}{76}\)

B = \(\frac{18}{76}\)

B = \(\frac{9}{38}\)

a)   Ư(a)={1;3;5;9;15;45}

b)   Ư(a)={1;7;11;77}

c)    Ư(a)={1;2;4;5;10;13;20;25;26;50;52;65;100;130;260;325;650;1300}

bằng 13/15 bạn ạ 

\(\dfrac{\dfrac{3}{4}-\dfrac{3}{5}+\dfrac{3}{7}+\dfrac{3}{11}}{\dfrac{13}{4}-\dfrac{13}{5}+\dfrac{13}{7}-\dfrac{13}{11}}\\ =\dfrac{\dfrac{1311}{1540}}{\dfrac{2041}{1540}}\\ =\dfrac{1311}{2041}\)

bn ơi có cách tính nào nhanh hơn ko bn