bài 2:tính
a).4/5+17/25 b).7/3-5/6 c).1+2/3
ai làm đủ các bước thì mình tick nhé
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a)
= 8/22 + 5/22
= 11/22
= 1/2
b)
= 24/8 - 3/8
= 21/8
c)
= 45/25
= 9/5
d)
= 3/7 x 1/4
= 3/28
:)
Answer:
Bài 1:
\(\left(135-35\right).\left(-37\right)+37.\left(-42-58\right)\)
\(=100.\left(-37\right)+37.\left(-100\right)\)
\(=\left(-3700\right)+\left(-3700\right)\)
\(=-7400\)
\(-65.\left(87-17\right)-87.\left(17-65\right)\)
\(=\left(-65\right).87-\left(-65\right).17-87.17+87.65\)
\(=-\left(-65\right).17-87.17\)
\(=17.\left(65-87\right)\)
\(=-374\)
\([3.\left(-2\right)-\left(-8\right)].\left(-7\right)-\left(-2\right).\left(-5\right)\)
\(=[\left(-6\right)+8].\left(-7\right)-\left(-2\right).\left(-5\right)\)
\(=2.\left(-7\right)-10\)
\(=-24\)
Bài 2:
\(\left(-55\right).\left(-25\right).\left(-8\right)\)
\(=\left(-55\right).[\left(-25\right).\left(-8\right)]\)
\(=\left(-55\right).200\)
\(=-11000\)
\(\left(-1\right).\left(-2\right).\left(-3\right).\left(-4\right).\left(-5\right).10\)
\(=[\left(-1\right).10].[\left(-2\right).\left(-5\right)].[\left(-3\right).\left(-4\right)]\)
\(=\left(-10\right).10.12\)
\(=-1200\)
Bài 1: Thực hiện các phép tính sau:
\(a)\)Chưa rỏ đề
\(b)\)\(5025\div5-25\div5\)
\(=\)\(1005-5\)
\(=\)\(1000\)
\(c)\)\(218-180\div2\div9\)
\(=\)\(218-10\)
\(=\)\(208\)
\(d)\)\(\left(328-8\right)\div32\)
\(=\)\(320\div32\)
\(=\)\(10\)
Bài 1:
a) ( Tôi không nhìn rõ đầu bài )
b) 5025 : 5 - 25 : 5
= ( 5025 - 25 ) : 5
= 5000 : 5
= 1000
c) 218 - 180 : 2 : 9
= 218 - 180 : ( 2 . 9 )
= 218 - 180 : 18
= 218 - 10
= 208
d) ( 328 - 8 ) : 32
= 320 : 32
= 10
a) \(x+\frac{4}{5}=\frac{3}{2}\)
\(\Rightarrow x=\frac{3}{2}-\frac{4}{5}\)
\(\Rightarrow x=\frac{7}{10}\)
Vậy \(x=\frac{7}{10}.\)
b) \(x-\frac{3}{2}=\frac{11}{4}\)
\(\Rightarrow x=\frac{11}{4}+\frac{3}{2}\)
\(\Rightarrow x=\frac{17}{4}\)
Vậy \(x=\frac{17}{4}.\)
c) \(\frac{25}{3-x}=\frac{5}{6}\)
\(\Rightarrow\left(3-x\right)5=25.6\)
\(\Rightarrow15-5x=150\)
\(\Rightarrow5x=15-150\)
\(\Rightarrow5x=-135\)
\(\Rightarrow x=-135:5\)
\(\Rightarrow x=-27\)
Vậy \(x=-27.\)
`@` `\text {Ans}`
`\downarrow`
`1,`
`a)`
`-7/25 + (-8)/25`
`= (-7 - 8)/25`
`= -15/25`
`= -3/5`
`b)`
`6/13 + (-15)/39`
`= 18/39 + (-15)/39`
`= (18 - 15)/39`
`= 3/39`
`= 1/13`
`c)`
`5/7 + 4/(-14)`
`= 10/14 + (-4)/14`
`= (10 - 4)/14`
`= 6/14`
`= 3/7`
`d)`
`-8/18 + (-15)/27`
`= -4/9 + (-5)/9`
`= (-4-5)/9`
`= -9/9 = -1`
`2,`
`a)`
`3/5 + (-7)/4`
`= 12/20 + (-35)/20`
`= (12 - 35)/20`
`=-23/20`
`b)`
`(-2) + (-5)/8`
`= (-16)/8 + (-5)/8`
`= (-16 - 5)/8`
`= -21/8`
`c)`
`1/8 + (-5)/9`
`= 9/72 + (-40)/72`
`= (9-40)/72`
`= -31/72`
`d)`
`6/13 + (-14)/39`
`= 18/39 + (-14)/39`
`= (18 - 14)/39`
`= 4/39`
`e)`
`(-18)/24 + 15/21`
`= (-3)/4 + 5/7`
`= (-21)/28 + 20/28`
`= (-21 + 20)/28`
`= -1/28`
\(\frac{17}{33}.\frac{2}{5}+\frac{3}{5}.\frac{17}{33}-\frac{17}{33}\)
\(=\frac{17}{33}\times\frac{2}{5}+\frac{3}{5}\times\frac{17}{33}-\frac{17}{33}\times1\)
\(=\frac{17}{33}\times\left(\frac{2}{5}+\frac{3}{5}-1\right)\)
\(=\frac{17}{33}\times\left(1-1\right)\)
\(=\frac{17}{33}\times0=\frac{17}{33}\)
a) \(\frac{2}{3}+\frac{5}{4}=\frac{8}{12}+\frac{15}{12}\)
\(=\frac{8+15}{12}=\frac{23}{12}\)
b) \(\frac{15}{25}+\frac{6}{21}=\frac{3}{5}+\frac{2}{7}\)
\(=\frac{21}{35}+\frac{10}{35}=\frac{31}{35}\)
c) \(\frac{35}{11}-2=\frac{35}{11}-\frac{22}{11}\)
\(=\frac{13}{11}\)
d) \(\frac{68}{17}-3=\frac{68}{17}-\frac{51}{17}\)
\(=1\)
Bài 1:
Ta có: \(x-35\%\cdot x=\dfrac{1}{25}\)
\(\Leftrightarrow65\%\cdot x=\dfrac{1}{25}\)
\(\Leftrightarrow x=\dfrac{1}{25}:\dfrac{13}{20}=\dfrac{1}{25}\cdot\dfrac{20}{13}=\dfrac{4}{65}\)
Vậy: \(x=\dfrac{4}{65}\)
Bài 2:
a) Ta có: \(17\dfrac{2}{31}-\left(\dfrac{15}{17}+6\dfrac{2}{31}\right)\)
\(=17\dfrac{2}{31}-\dfrac{15}{17}-6\dfrac{2}{31}\)
\(=11+\dfrac{2}{31}-\dfrac{15}{17}\)
\(=\dfrac{5366}{527}\)
\(a,\frac{4}{5}+\frac{17}{25}\)
\(=\frac{20}{25}+\frac{17}{25}\)
\(=\frac{37}{25}\)
\(b,\frac{7}{3}-\frac{5}{6}\)
\(=\frac{14}{6}-\frac{5}{6}\)
\(=\frac{9}{6}\)
\(=\frac{3}{2}\)
\(c,1+\frac{2}{3}\)
\(=\frac{3}{3}+\frac{2}{3}\)
\(=\frac{5}{3}\)
a) 4/5 + 17/25
= 20/25 + 17/25
= 37/25
b) 7/3 - 5/6
= 14/6 - 5/6
= 9/6
= 3/2
c) 1 + 2/3
= 3/3 + 2/3
= 5/3