5 x - 7 = 13
1. -2/9 x 15/17 + -2/9 x 2/17
2. -5/3 x 6/5 + -7/9 x 3/10
3. 15/20 x 7/5 + -9/7 x -6/4
4.-25/13 x 5/19 + -25/13 x 14/19
5 -7/13 x 13/5 + -9/7 x 5/3
6. 27/35 x 5/9 - 2/7 x -7/5
7. 10/13 x 13/5 + {-9/5} x 10/3
8. 100/27 x 9/20 + 40% x 5/3
9. 1,5 x 5/12 + 1/4 x 3/4
10. 2 1/2 x 7/5 + {-9/10} x 2/3
11. X + 45% = 2 1/2 -5/3
12. 80% + X = -5/2 + 3/4
13. 4/25 - X =-5/2 + -3/10
1: =-2/9(15/17+2/17)=-2/9
2: \(=\dfrac{-6}{3}+\dfrac{-21}{90}\)
=-2-7/30=-67/30
3: \(=\dfrac{3}{4}\cdot\dfrac{7}{5}+\dfrac{9}{7}\cdot\dfrac{3}{2}\)
=21/20+27/14=417/140
4: =-25/13(5/19+14/19)=-25/13
5: =-7/5-45/21=-7/5-15/7=-124/35
1: =-2/9(15/17+2/17)=-2/9
2: =34⋅75+97⋅32=34⋅75+97⋅32
=21/20+27/14=417/140
4: =-25/13(5/19+14/19)=-25/13
5: =-7/5-45/21=-7/5-15/7=-124/35
1. -2/9 x 15/17 + -2/9 x 2/17
2. -5/3 x 6/5 + -7/9 x 3/10
3. 15/20 x 7/5 + -9/7 x -6/4
4.-25/13 x 5/19 + -25/13 x 14/19
5 -7/13 x 13/5 + -9/7 x 5/3
`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`
-5/7 x 3/13 - 5/7 x 10/13 + 12/7
`-5/7xx3/13-5/7xx10/13+12/7`
`=-5/7xx(3/13+10/13)+12/7`
`=-5/7xx13/13+12/7=-5/7+12/7=7/7=1`
=-5/7x(3/13 + 10/13) +12/7
=-5/7x1+12/7
= -5/7+ 12/7
= 7/7 =1
7/13 x 7/15 - 5/12 x 7/13 + 7/13 x 8/15 = ?
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
12/13×8/15×7/9=........................
........................
Giúp mik câu này mik đag cần gấp
Tính :
1)3/5 x1/7 +3/5 x6/7 -3/5
2)6/7 x4/9 + 6/7 x5/9 + 6/7
3) 9/13 x 7/12 + 9/13 x 5/12 - 9/13
4) 4/13 x5/12 +4/13 x 7/12 - 4/13
1) = \(\frac{3}{5}\)
2) =\(\frac{6}{7}\)
3)\(\frac{9}{13}\)
4)\(\frac{4}{13}\)
Câu 13 : (-1/4 + 5/8 ) + -3/5
Câu 14 : M = 5/9 x 7/13 + 5/9 x 9/13 - 5/9 x 3/13
câu 15 : E = (-3/4 + 2/5) : 3/7 + (3/5 + -1/4) : 3/7
Câu 16 : H = 7/8 : (2/9 - 1/8) + 7/8 : (1/36 - 5/12)
Câu 13 :
\(\left(-\frac{1}{4}+\frac{5}{8}\right)+-\frac{3}{5}\)
\(=\frac{3}{8}-\frac{-3}{5}\)
\(=\frac{39}{40}\)
Câu 14 :
\(M=\frac{5}{9}.\frac{7}{13}+\frac{5}{9}.\frac{9}{13}-\frac{5}{9}.\frac{3}{13}\)
\(=\frac{5}{9}.\left(\frac{7}{13}+\frac{9}{13}-\frac{3}{13}\right)\)
\(=\frac{5}{9}.1=\frac{5}{9}\)
Câu 15 :
\(E=\left(-\frac{3}{4}+\frac{2}{5}\right):\frac{3}{7}+\left(\frac{3}{5}+\frac{-1}{4}\right):\frac{3}{7}\)
\(E=\left(-\frac{3}{4}+\frac{2}{5}+\frac{3}{5}+\frac{-1}{4}\right):\frac{3}{7}\)
\(E=0\)
Câu 16 :
\(H=\frac{7}{8}:\left(\frac{2}{9}-\frac{1}{8}\right)+\frac{7}{8}:\left(\frac{1}{36}-\frac{5}{12}\right)\)
\(=\frac{7}{8}:\left(\frac{2}{9}-\frac{1}{8}+\frac{1}{36}-\frac{5}{12}\right)\)
\(=\frac{7}{8}:\frac{-7}{24}=-3\)
huhuhuhuhuhuhuhuhuhuhuhuhu giúp mk đi
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Câu 14:
M = \(\frac{5}{9}\) \(.\) \(\frac{7}{13}\) \(+\) \(\frac{5}{9}\) \(.\) \(\frac{9}{13}\) \(-\) \(\frac{5}{9}\) \(.\) \(\frac{3}{13}\)
M = \(\frac{5}{9}\) \(.\) ( \(\frac{7}{13}\)\(+\) \(\frac{9}{13}\) \(-\) \(\frac{3}{13}\))
M = \(\frac{5}{9}\) \(.\) \(1\)
M = \(\frac{5}{9}\)
Tính nhanh:
a) âm 5/13 - { 3/5 + 3/13 - 4/10 }
b) âm 5/7 x 2/11 + 5/7 x -9/11 + ^ một 5/7
c) 1/10 + 1/15 + 1/21 + .... + 1/66
d) 6/7 x 7/13 + 6/13 x 9/7 - 3/13 x 6/7
## Mấy bn cố giup mik nhanh thật nhanh nha, mik cần gấp. Bạn nào nhanh ngay tì mik tick luôn h nhé!! Cảm ơn nhiu!
Tính nhanh:
a)11/7 x 8/13 + 8/13 x 3/7 + 8/13
b)5/7 x 8/13 + 8/13 x 9/7 - 8/13
c)156 x 199 - 57 x 199 - 199
a.11/7.8/13+8/13.3/7+8/13
=8/13.(11/7+3/7+1)
=8/13.3
=24/13
b.5/7.8/13+8/13.9/7-8/13
=8/13.(5/7+9/7-1)
=8/13.1
=8/13
c.157.199-56.199-199
=199.(157-56-1)
=199.100
19900
a, 2/3 . x = 2/7 b, x . 3/5 = 2/5 c, x : 8/13 = 13/7 d, 3/2 : x = 7/4
a
=> \(x=\dfrac{2}{7}:\dfrac{2}{3}=\dfrac{2.3}{2.7}=\dfrac{3}{7}\)
b
=> \(x=\dfrac{2}{5}:\dfrac{3}{5}=\dfrac{2.5}{3.5}=\dfrac{2}{3}\)
c
=> \(x=\dfrac{13}{7}.\dfrac{8}{13}=\dfrac{13.8}{7.13}=\dfrac{8}{7}\)
d
=> \(x=\dfrac{3}{2}:\dfrac{7}{4}=\dfrac{3.2.2}{2.7}=\dfrac{6}{7}\)
a: 2/3*x=2/7
=>x=2/7:2/3=3/7
b: x*3/5=2/5
=>x=2/5:3/5=2/5*5/3=10/15=2/3
c: x:8/13=13/7
=>x=13/7*8/13=8/7
d: 3/2:x=7/4
=>x=3/2:7/4=3/2*4/7=12/14=6/7
a) \(\dfrac{2}{3}\cdot x=\dfrac{2}{7}\)
\(\Rightarrow x=\dfrac{2}{7}:\dfrac{2}{3}\)
\(\Rightarrow x=\dfrac{2}{7}\cdot\dfrac{3}{2}\)
\(\Rightarrow x=\dfrac{3}{7}\)
b) \(x\cdot\dfrac{3}{5}=\dfrac{2}{5}\)
\(\Rightarrow x=\dfrac{2}{5}:\dfrac{3}{5}\)
\(\Rightarrow x=\dfrac{2}{5}\cdot\dfrac{5}{3}\)
\(\Rightarrow x=\dfrac{2}{3}\)
c) \(x:\dfrac{8}{13}=\dfrac{13}{7}\)
\(\Rightarrow x=\dfrac{8}{13}\cdot\dfrac{13}{7}\)
\(\Rightarrow x=\dfrac{8}{7}\)
d) \(\dfrac{3}{2}:x=\dfrac{7}{4}\)
\(\Rightarrow x=\dfrac{3}{2}:\dfrac{7}{4}\)
\(\Rightarrow x=\dfrac{3}{2}\cdot\dfrac{4}{7}\)
\(\Rightarrow x=\dfrac{6}{7}\)
Tính bằng cách thuận tiên nhất:
1):(3/4 x 5/97 + 1/9 x 13/47) x (1/5 - 7/25 x 5/7)
2): 8/17 x 4/15 + 8/17 x 22/15 - 8/15 x 9/17
3): 2021/2 x 1/3 + 4042/4 x 1/5 + 6063/3 x 22/15
4); 4/7 x 2/13 + 8/13 :7/4 + 4/7 : 13/2 + 4/7 x 1/13
5): 2022 x 2021 - 1/ 2021 + 2022 x 2020
6): 18 x 123 + 9 x 4567 x 2 + 3 x 5310 x 6 / (2 + 4 + 6 + 8 + ...+20 + 22) + 48
7): A= 2021 x 2021 x 202020 - 2020 x 2020 x 20212021 / 2020 x 20192019
1) Ta có: \(\left(\dfrac{3}{4}\cdot\dfrac{5}{97}+\dfrac{1}{9}\cdot\dfrac{13}{47}\right)\cdot\left(\dfrac{1}{5}-\dfrac{7}{25}\cdot\dfrac{5}{7}\right)\)
\(=\left(\dfrac{3}{4}\cdot\dfrac{5}{97}+\dfrac{1}{9}\cdot\dfrac{13}{47}\right)\cdot\left(\dfrac{1}{5}-\dfrac{1}{5}\right)\)
=0
2) Ta có: \(\dfrac{8}{17}\cdot\dfrac{4}{15}+\dfrac{8}{17}\cdot\dfrac{22}{15}-\dfrac{8}{15}\cdot\dfrac{9}{17}\)
\(=\dfrac{8}{17}\left(\dfrac{4}{15}+\dfrac{22}{15}-\dfrac{9}{15}\right)\)
\(=\dfrac{8}{17}\cdot\dfrac{15}{15}=\dfrac{8}{17}\)
3) Ta có: \(\dfrac{2021}{2}\cdot\dfrac{1}{3}+\dfrac{4042}{4}\cdot\dfrac{1}{5}+\dfrac{6063}{3}\cdot\dfrac{22}{15}\)
\(=\dfrac{2021}{2}\left(\dfrac{1}{3}+\dfrac{1}{5}\right)+2021\cdot\dfrac{22}{15}\)
\(=\dfrac{2021}{2}\cdot\dfrac{8}{15}+\dfrac{2021}{2}\cdot\dfrac{44}{15}\)
\(=\dfrac{2021}{2}\cdot\dfrac{52}{15}\)
\(=\dfrac{52546}{15}\)
4) Ta có: \(\dfrac{4}{7}\cdot\dfrac{2}{13}+\dfrac{8}{13}:\dfrac{7}{4}+\dfrac{4}{7}:\dfrac{13}{2}+\dfrac{4}{7}\cdot\dfrac{1}{13}\)
\(=\dfrac{4}{7}\left(\dfrac{2}{13}+\dfrac{8}{13}+\dfrac{2}{13}+\dfrac{1}{13}\right)\)
\(=\dfrac{4}{7}\)