a, \(-\dfrac{315}{540}\) = \(\dfrac{-315:45}{540:45}\) = \(\dfrac{-7}{12}\)        b,   \(\dfrac{25.13}{26.35}\) = \(\dfrac{25.13:5:13}{26.35:13:5}\) = \(\dfrac{5}{14}\)

c,     \(\dfrac{6.9-2.17}{63.3-119}\) = \(\dfrac{2.3.9-2.17}{7.9.3-7.17}\) = \(\dfrac{2.(27-17)}{7.(7-17)}\) = \(\dfrac{2}{7}\)

d, \(\dfrac{3.13-13.18}{15.40-80}\) = \(\dfrac{3.13(1-6)}{40.(15-2)}\) = \(\dfrac{-3.13.5}{40.13}\) = \(\dfrac{-15}{40}\) = \(\dfrac{-15:5}{40:5}\) = \(-\dfrac{3}{8}\)

giúp mik đi nhé 

mik đang cần gấp nèeee

a,-7/12

b,5/14

c,-3/8

d,-1

A,-315/ 540 = -315 : 45/ 540 : 45 = -7/ 12

B, 25.13/26.35 = 5.5.13/ 2.13.5.7 = 5/ 2.7 = 5/ 14

C, 6.9 - 2.17/ 63.3 - 119 = 2.3.9 - 2.17/ 7.9.3 - 7.17 = 2.27 - 2.17/ 7.27 - 7.17

                                    = 2( 27 - 17)/ 7(27 - 17) = 2/ 7

D, 2929 - 101/ 2.1919+404 = 29.101 - 101.1/ 2.19.101+101.4

                                        = 101(29 - 1)/ 38.101+ 4.101

                                         = 101.28/ (38+4)101

                                         = 101.28/ 42.101 

                                         = 28/ 42 = 2/ 3

Đặt A = \(\frac{3.13-13.18}{15.40-80}\)

=> A  = \(\frac{13.\left(3-18\right)}{15.40-80}\)

=> A = \(\frac{13.\left(-15\right)}{15.40-40.2}\)

=> A = \(\frac{13.\left(-15\right)}{40.\left(15-2\right)}\)

=> A = \(\frac{13.\left(-15\right)}{40.13}\)

=> A = \(\frac{-15}{40}\)

=> A = \(\frac{-3}{8}\)

Làm tiếp đi bạn Cô nàng cự giải

a, \(\dfrac{25.13}{26.35}=\dfrac{5.1}{2.7}=\dfrac{5}{14}.\)

b, \(\dfrac{6.9-2.17}{63.3-119}=\dfrac{2.3.9-2.17}{9.7.3-17.7}=\dfrac{2\left(3.9-17\right)}{7\left(9.3-17\right)}=\dfrac{2}{7}.\)

c, \(\dfrac{3.13-13.18}{15.40-80}=\dfrac{13\left(3-18\right)}{15.40-40.2}=\dfrac{13.\left(-15\right)}{40\left(15-2\right)}=\dfrac{13.\left(-15\right)}{40.13}=\dfrac{-15}{40}=\dfrac{-3}{8}.\)d, \(\dfrac{2929-101}{2.1919+404}=\dfrac{29.101-101.1}{2.19.101+101.4}=\dfrac{101\left(29-1\right)}{38.101+101.4}=\dfrac{101\left(29-1\right)}{101\left(38+4\right)}=\dfrac{29-1}{38+4}=\dfrac{28}{42}=\dfrac{2}{3}.\)

(còn tiếp!!!)

~ Chúc bn học tốt!!! ~

Rút gọn các phân số sau:

a, \(\dfrac{-315}{540}\) = \(\dfrac{-315:45}{540:45}\) = \(\dfrac{-7}{12}\)

b, \(\dfrac{25.13}{26.35}\) = \(\dfrac{5.5.13}{13.2.5.7}\) = \(\dfrac{5}{2.7}\) = \(\dfrac{5}{14}\)

c, \(\dfrac{3.13-13.18}{15.40-80}\) = \(\dfrac{3.13-13.18}{15.40-2.40}\) = \(\dfrac{13.\left(3-18\right)}{40.\left(15-2\right)}\)

= \(\dfrac{13.\left(-15\right)}{40.13}\) = \(\dfrac{-3}{8}\)

a) \(\dfrac{-315}{540}=\dfrac{-315:45}{540:45}=\dfrac{-7}{12}\)

b) \(\dfrac{25\cdot13}{26\cdot35}=\dfrac{5\cdot5\cdot13}{2\cdot13\cdot5\cdot7}=\dfrac{5}{2\cdot7}=\dfrac{5}{14}\)

c) \(\dfrac{3\cdot13-13\cdot18}{15\cdot40-80}=\dfrac{3\cdot13-13\cdot18}{15\cdot40-2\cdot40}=\dfrac{13\cdot\left(3-18\right)}{40\left(15-2\right)}=\dfrac{13\cdot\left(-15\right)}{40\cdot13}=\dfrac{1\cdot\left(-3\right)}{8\cdot1}=\dfrac{-3}{8}\)

a)\(\frac{-315}{540}\)=\(\frac{7}{12}\)

b)\(\frac{25.13}{26.35}\)=\(\frac{5}{14}\)

c)\(\frac{6.9-2.17}{63.3-119}\)=\(\frac{4}{7}\)

d)\(\frac{2929-101}{2.1919+404}\)=\(\frac{2}{3}\)

a, \(\frac{-7}{12}\)                                         b, \(\frac{5}{14}\)                                         c,\(\frac{-20}{41}\)                          d, \(\frac{2}{3}\)

k mình nha

Trả lời:

a, \(\frac{6\times9-2\times17}{63\times3-119}=\frac{2.3\times9-2\times17}{7.9\times3-7.17}\)

                                     \(=\frac{2\times\left(3\times9-17\right)}{7\times\left(3\times9-17\right)}\)

                                     \(=\frac{2}{7}\)

b, \(\frac{3\times13-13\times18}{15\times40-80}=\frac{13\times\left(3-18\right)}{40\times\left(15-2\right)}\)

                                           \(=\frac{13\times-15}{40\times13}\)

                                           \(=\frac{-3}{8}\)

c, \(\frac{-1997.1996+1}{\left(-1995\right).\left(-1997\right)+1996}=\frac{-1997.1996+1}{\left(1-1996\right).\left(-1997\right)+1996}\)

                                                              \(=\frac{-1997.1996+1}{-1997-1996.\left(-1997\right)+1996}\)

                                                              \(=\frac{-1997.1996+1}{-1996.\left(-1997\right)-1}\)

                                                              \(=\frac{-1997.1996+1}{-\left[1996.\left(-1997\right)+1\right]}\)

                                                               \(=-1\)

d, \(\frac{3.7.13.37.39-10101}{505050-70707}=\frac{10101.39-10101}{50.10101-7.10101}\)

                                                   \(=\frac{10101.\left(39-1\right)}{10101.\left(50-7\right)}\)

                                                   \(=\frac{10101.38}{10101.43}\)

                                                   \(=\frac{38}{43}\)

b) \(\dfrac{6\cdot9-2\cdot17}{63\cdot3-119}\)

\(=\dfrac{2\left(3\cdot9-17\right)}{7\cdot\left(3\cdot9-17\right)}\)

\(=\dfrac{2}{7}\)