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Mk chỉ biết câu a thôi
a) \(\frac{\frac{5}{7}+\frac{5}{9}-\frac{5}{11}}{\frac{15}{7}+\frac{15}{9}-\frac{15}{11}}\)
= \(\frac{5\cdot\left(\frac{1}{7}+\frac{1}{9}-\frac{1}{11}\right)}{15\cdot\left(\frac{1}{7}+\frac{1}{9}-\frac{1}{11}\right)}\)
= \(\frac{5}{15}\)
= \(\frac{1}{3}\)
Chúc bạn học tốt
\(A=\dfrac{5}{11}.\dfrac{5}{7}+\dfrac{5}{11}.\dfrac{2}{7}+\dfrac{6}{11}=\dfrac{5}{11}\left(\dfrac{5}{7}+\dfrac{2}{7}\right)+\dfrac{6}{11}=\dfrac{5}{11}.1+\dfrac{6}{11}=\dfrac{5}{11}+\dfrac{6}{11}=\dfrac{11}{11}=1\)
\(B=\dfrac{3}{13}.\dfrac{6}{11}+\dfrac{3}{13}.\dfrac{9}{11}-\dfrac{3}{13}.\dfrac{4}{11}=\dfrac{3}{13}\left(\dfrac{6}{11}+\dfrac{9}{11}-\dfrac{4}{11}\right)=\dfrac{3}{13}.1=\dfrac{3}{13}\)
\(C=\left(\dfrac{12}{16}-\dfrac{31}{22}+\dfrac{14}{91}\right)\left(\dfrac{1}{2}-\dfrac{1}{3}-\dfrac{1}{6}\right)=\left(\dfrac{12}{16}-\dfrac{31}{22}+\dfrac{14}{91}\right)\left(\dfrac{3}{6}-\dfrac{2}{6}-\dfrac{1}{6}\right)=\left(\dfrac{12}{16}-\dfrac{31}{22}+\dfrac{14}{91}\right).0=0\)
a: \(3^8:3^4+2^2\cdot2^3\)
=81+32
=123
b: \(3\cdot4^2-2\cdot3^2\)
\(=48-18\)
=30
a, 38: 34+ 22. 23
= 38-4 + 22+3
= 34 + 25
= 81 + 32
= 113
b, 3 . 42- 2 . 32
= 3 . 16 - 2 . 9
= 48 - 18
= 30
c, 84 : 4 + 39: 37+ 50
= 84 : 4 + 32 + 1
= 84 : 4 + 9 + 1
= 21 + 9 + 1
= 31
d, 295 - ( 31 - 22 . 5)2
= 295 - ( 31 - 4 . 5 )2
= 295 - ( 31 - 20 )2
= 295 - 112
= 295 - 121
= 174
e, 500 - {5[409 - (23 . 3 - 21)2 ] + 103 } : 15
= 500 - {5[409 - (8 . 3 - 21)2 ] + 103 } : 15
= 500 - {5[409 - (24 - 21)2 ] + 103 } : 15
= 500 - {5[409 - 32 ]+ 103 } : 15
= 500 - {5[409 - 9 ]+ 103 } : 15
= 500 - {5 . 400 + 1000 } : 15
= 500 - {2000 + 1000} : 15
= 500 - 3000 : 15
= 500 - 200
= 300
g, 53 . 2 - 100 : 4 + 23 . 5
= 125 . 2 - 100 : 4 + 8 . 5
= 250 - 25 + 40
= 225 + 40
= 265
h, 205 - [1200 - (42 - 2 . 3)3 ] : 40
= 205 - [ 1200 - ( 16 - 2 . 3 )3 : 40
= 205 - [ 1200 - ( 16 - 6 )3 ] : 40
= 205 - [ 1200 - 103 ] : 40
= 205 - [ 1200 - 1000 ] : 40
= 205 - 200 : 40
= 205 - 5
= 200
Đây nha bạn!!!
`a)3/5+(-4/9)`
`=3/5-4/9`
`=27/45-20/45`
`=7/45`
`b)3/5+2/5 . 15/8`
`=3/5 + 30/40`
`=3/5+3/4`
`=12/20+15/20`
`=27/20`
`c)7/2 . 8/13 + 8/13 . (-5/2)`
`=8/13 . (7/2 +(-5)/2)`
`=8/13 . 1`
`=8/13`
`d)-5/17 . (-9/23)+9/23 . (-22/17) + 11 9/23`
`=-5/17 . (-9/23) + 9/23 . (-1) . 22/17 + 11 + 9/23`
`=-5/17 . (-9/23) + (-9/23) . 22/17+11+9/23`
`= -9/23 ( -5/17 + 22/17)+11+9/23`
`= - 9/23 . 1+11+9/23`
`=-9/23+11+9/23`
`=(-9/23+9/23)+11`
`=0+11`
`=11`
a: =27/45-20/45=7/45
b: =3/5+30/40
=3/5+3/4
=12/20+15/20
=27/20
c: =8/13(7/2-5/2+1)=8/13*2=16/13
d: =9/23*5/17-9/23*22/17+11+9/23
=-9/23+11+9/23
=11
1: \(=-\dfrac{3}{4}+3-\dfrac{1}{4}-\dfrac{5}{4}+\dfrac{9}{2}=-\dfrac{9}{4}+3+\dfrac{9}{2}=\dfrac{-9+12+18}{4}=\dfrac{21}{4}\)
2: \(=\dfrac{-5}{7}\left(\dfrac{13}{19}+\dfrac{6}{19}\right)+\dfrac{5}{7}=\dfrac{-5}{7}+\dfrac{5}{7}=0\)
3: \(=\dfrac{2}{5}\left(1-\dfrac{8}{3}-\dfrac{5}{8}\right)=\dfrac{2}{5}\cdot\dfrac{-55}{24}=\dfrac{-11}{12}\)
a) 4 + 4 73 − 4 115 5 + 5 73 − 1 23 = 4 1 + 1 73 − 1 115 5 1 + 1 73 − 1 115 = 4 5
b) 5 22 + 3 13 − 1 2 4 13 − 2 11 + 3 2 = 65 + 66 − 143 286 88 − 52 + 429 286 = − 12 286 465 286 = − 4 155