K
Khách
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11 tháng 2 2022
\(\dfrac{5}{13}.\dfrac{8}{15}+\dfrac{5}{13}.\dfrac{26}{15}-\dfrac{5}{13}.\dfrac{8}{15}.\\ =\dfrac{5}{13}.\left(\dfrac{8}{15}+\dfrac{26}{15}-\dfrac{8}{15}\right).\\ =\dfrac{5}{13}.\dfrac{26}{15}=\dfrac{2}{3}.\)
31 tháng 8 2021
Ta có: \(B=\dfrac{5}{13}\cdot\dfrac{8}{15}+\dfrac{5}{13}\cdot\dfrac{26}{15}-\dfrac{5}{13}\cdot\dfrac{8}{15}\)
\(=\dfrac{5}{13}\cdot\dfrac{26}{15}\)
\(=\dfrac{130}{195}=\dfrac{2}{3}\)
KH
Thực hiện phép tính
-a) -5/7.7/10-3/11:6/5
b) 5/14.1/3.-4/15:5/7
c) 2 13/15.11/15-13/15+2 13/15 . 4/15
1
1 tháng 5 2019
a) -5/7.7/10 - 3/11 : 6/5
= -1/2 - 5/22
= -8/11
b) 5/14.1/3.-4/15:5/7
= -2/63:5/7 = -2/45
c) 2 13/15.11/15 - 13/15 + 2 13/15.4/15
= 2 13/15.(11/15 + 4/15) - 13/15
= 2 13/15.1 - 13/15
= 2 13/15 - 13/15
= 2
Y
13 tháng 6 2023
\(\dfrac{12}{17}.\dfrac{9}{13}-\dfrac{7}{15}.\dfrac{6}{13}+\dfrac{5}{17}.\dfrac{9}{13}-\dfrac{8}{15}.\dfrac{6}{13}\)
\(=\dfrac{9}{13}.\left(\dfrac{12}{17}+\dfrac{5}{17}\right)-\dfrac{6}{13}.\left(\dfrac{7}{15}+\dfrac{8}{15}\right)\)
\(=\dfrac{9}{13}.\dfrac{17}{17}-\dfrac{6}{13}.\dfrac{15}{15}\)
\(=\dfrac{9}{13}.1-\dfrac{6}{13}.1\)
\(=\dfrac{9}{13}-\dfrac{6}{13}\)
\(=\dfrac{9-6}{13}\)
\(=\dfrac{3}{13}\)
8 tháng 8 2019
\(23\frac{13}{15}\cdot\frac{-11}{5}+13\frac{2}{15}:\frac{-5}{11}+\left(\frac{3}{2}\right)^2\)
\(< =>\frac{358}{15}\cdot\frac{-11}{5}+\frac{197}{15}:\frac{-5}{11}+\left(\frac{3}{2}\right)^2\)
\(< =>\frac{-3938}{75}+\frac{-2167}{75}+\left(\frac{3}{2}\right)^2\)
\(< =>\frac{-407}{5}+\left(\frac{3}{2}\right)^2\)
\(< =>\frac{-1583}{20}\)
PK
2
BS
29 tháng 1 2023
\(a,\dfrac{1}{2}+\left(-\dfrac{3}{4}\right)=\dfrac{2}{4}+\left(-\dfrac{3}{4}\right)=-\dfrac{1}{4}\)
\(b,\dfrac{2}{5}+\left(-\dfrac{1}{16}\right)+\left(-\dfrac{9}{5}\right)+\left(-\dfrac{5}{16}\right)=\left(\dfrac{2}{5}-\dfrac{9}{5}\right)-\left(\dfrac{1}{16}+\dfrac{5}{16}\right)=\dfrac{-7}{5}-1=\dfrac{-12}{5}\)
\(c,\dfrac{-2}{13}+\dfrac{8}{15}+\dfrac{10}{20}+\dfrac{15}{13}+\left(-\dfrac{23}{15}\right)=\left(\dfrac{-2}{13}+\dfrac{15}{13}\right)+\left(\dfrac{8}{15}+\dfrac{-23}{15}\right)+\dfrac{1}{2}=1+\left(-1\right)+\dfrac{1}{2}=\dfrac{1}{2}\)
BS
29 tháng 1 2023
(Cho mik làm lại nha)
\(a,\dfrac{1}{2}+\left(-\dfrac{3}{4}\right)=\dfrac{2}{4}+\left(-\dfrac{3}{4}\right)=-\dfrac{1}{4}\)
\(a,\dfrac{2}{5}+\left(-\dfrac{1}{16}\right)+\left(-\dfrac{9}{5}\right)+\left(-\dfrac{5}{16}\right)=\left(\dfrac{2}{5}+\dfrac{-9}{5}\right)-\left(\dfrac{1}{16}+\dfrac{5}{16}\right)=\dfrac{-7}{5}-\dfrac{6}{16}=\dfrac{-71}{40}\)
\(c,\dfrac{-2}{13}+\dfrac{8}{15}+\dfrac{10}{20}+\dfrac{15}{13}+\left(-\dfrac{23}{15}\right)=\left(\dfrac{-2}{13}+\dfrac{15}{13}\right)+\left(\dfrac{8}{15}+\dfrac{-23}{15}\right)+\dfrac{1}{2}=1+\left(-1\right)+\dfrac{1}{2}=\dfrac{1}{2}\)
2 tháng 2 2016
7/13 x 7/15 - 5/12 x 7/13 + 7/13 x 8/15 =7/13x(7/15-5/12+8/15)=7/13x7/12=49/156
1 tháng 3
12/13×8/15×7/9=........................
........................
ND
Nguyễn Đức Trí
VIP
21 tháng 7 2023
...=-15-9=-24
...=4+7=11
...=-12-13=-25
...=13+10=23
...=-4-7=-11
...=-9+13=4
...=12+0=12
...=0-7=-7
...=0+3=3
...=15-17=-2
...=-6
...=-23
...=15-15=0
H
10 tháng 7 2023
`1, -2/9 xx 15/17 + (-2/9) xx 2/17`
`= -2/9 xx (15/17 + 2/17)`
`= -2/9 xx 17/17`
`=-2/9xx1`
`=-2/9`
__
`-5/3 xx 6/5 + (-7/9) xx 3/10`
`= -30/15 + (-21/90)`
`= -2 + (-7/30)`
`=-60/30 +(-7/30)`
`=-67/30`
__
`15/20 xx 7/5 + (-9/7) xx (-6/4)`
`=3/4 xx7/5 + (-9/7) xx(-6/4)`
`= 21/20 + 54/28`
`= 21/20 + 27/14`
`=417/140`
__
`-25/13 xx 5/19 + (-25/13) xx 14/19`
`=-25/13 xx (5/19 +14/19)`
`=-25/13 xx 19/19`
`= -25/13 xx 1`
`=-25/13`
__
`-7/13 xx 13/5 + (-9/7) xx 5/3`
`=-7/5 +(-15/7)`
`=-124/35`
\(-13+15+5\)
\(=-13+\left(5+15\right)\)
\(=-13+20\)
\(=20-13\)
\(=7\)
$-13+15+5$
$=-13+(15+5)$
$=-13+20$
$=7$