`(5/6-2/3).36^2 + ( (-1)/2)^2 : ( (-1)/2`
Câu 15 A= 1/3-3/4+3/5+1/2007-1/36+1/25-2/9
Câu 16 A=1/3- 3/4- (-3/5)+ 1/64- 2/9- 1/36+ 1/15
Câu 17 A=1/2- 2/3+ 3/4- 4/5+ 5/6- 6/7- 5/6+ 4/5- 3/4+ 2/3- 1/2
15: A= 1/3-3/4+3/5+1/2007-1/36+1/15-2/9
Sửa đề:
A=-3/4-2/9-1/36+1/3+3/5+1/15+1/2007
=-27/36-8/36-1/36+5/15+9/15+1/15+1/2007
=-1+1+1/2007=1/2007
16:
\(A=\dfrac{1}{3}+\dfrac{3}{5}+\dfrac{1}{15}-\dfrac{3}{4}-\dfrac{2}{9}-\dfrac{1}{36}+\dfrac{1}{64}\)
\(=\dfrac{5+9+1}{15}+\dfrac{-27-8-1}{36}+\dfrac{1}{64}\)
=1/64
17:
=1/2-1/2+2/3-2/3+3/4-3/4+4/5-4/5+5/6-5/6-6/7
=-6/7
bài 1:
1/4 + 2/3 2/7 + 2/3 2/5 + 1/3 2/3 + 1/2 1/3 + 3/5 4/5 + 1/3
1/8 + 3/4 1/36 + 5/12 1/3 + 1/6 + 1/18.
bài 2:
15/16 - 3/16 17/18 - 5/6 3/4 - 4/9 1/2 - 2/5 5/6 - 3/10 3-1/3
4/5 - 1/10 5/2 - 1 5/8 - 2/5.
B=(-5/3+2/5):4/5+(-1/3+8/5):4/5 C=1/2-2/3-(-1/3)+1/69-(2/9)+1/6-(1/36)
\(B=\left(\dfrac{-5}{3}+\dfrac{2}{5}\right):\dfrac{4}{5}+\left(\dfrac{-1}{3}+\dfrac{8}{5}\right):\dfrac{4}{5}\)
\(B=\dfrac{-5}{3}+\dfrac{2}{5}:\dfrac{4}{5}+\dfrac{-1}{3}+\dfrac{8}{5}:\dfrac{4}{5}\)
\(B=\left(\dfrac{-5}{3}+\dfrac{-1}{3}\right)+\left(\dfrac{2}{5}+\dfrac{8}{5}\right):\dfrac{4}{5}\)
\(B=\left[\left(-2\right)+2\right]:\dfrac{4}{5}\)
\(B=0:\dfrac{4}{5}=0\)
\(=>B=\dfrac{5}{4}\cdot\left(-\dfrac{5}{3}+\dfrac{2}{5}-\dfrac{1}{3}+\dfrac{8}{5}\right)=\dfrac{5}{4}\cdot\left(-2+2\right)=\dfrac{5}{4}\cdot0=0\)
\(=>C=\left(-\dfrac{2}{3}+\dfrac{1}{3}+\dfrac{1}{6}+\dfrac{1}{2}\right)+\left(\dfrac{1}{69}-\dfrac{1}{36}-\dfrac{2}{9}\right)\)
\(C=\left(-\dfrac{2}{6}+\dfrac{1}{6}+\dfrac{3}{6}\right)-\dfrac{65}{276}=\dfrac{1}{3}-\dfrac{65}{276}=\dfrac{157}{276}\)
a)(5+1/5-2/9)-(2-1/23-3/35+5/6)-(8+2/7-1/18)
b) 1/3-3/4(-3/5+1/64- -2/9-1/36+1/15
c) -5/7-(-5/67)+13/10+1/2+(-1/6)+1 3/14-(-2/5)
d)3/5:(-1/15-1/6)+3/5:(-1/3-1 1/15)
[-1/2-[-3/5]+[-1/9+1/71-[-2/7]+4/35-7/18
1/3-3/4-[-3/5]+1/64-2/9-1/36+1/15
-5/7-[-5/67]+13/30+1/2+[-11/6]+17/14-[-2/5]
[3-1/4+2/3]-[5-1/3-6/5]-[6-7/4+3/2]
[5+1/5-2/9]-[2-1/23-73/35+5/6]-[8+2/7-1/18]
làm giúp mình mình đang cần gấp
Tính :
5/2 - 2/3 + 5/4=
20/12 + 36/18 - 21/28=
1/2 - 1/6 - 1/9 =
`5/2 - 2/3 + 5/4`
`= 30/12 - 8/12 + 15/12`
`= (30-8+15)/12`
`= 37/12`
`----`
`20/12 + 36/18 -21/28`
`= 5/3 + 2-3/4`
`= 20/12 + 24/12 -9/12`
`= 35/12`
`5/2-2/3+5/4`
`=30/12-8/12+15/12`
`=37/12`
`20/12+36/18-21/28`
`=5/3+2-3/4`
`=20/12+24/12-9/12`
`=35/12`
Bài 2. > , < , = ?
5/7… 4/3 2/5 …… 6/10 1/4 …… 3/12 27/36 ….. 2/9 7/6 …… 7/9
7/2 …… 2/7 15/23........1 27/9.......2 14/15........1 51/17........4
Bài 2. > , < , = ?
5/7 < 4/3 2/5 < 6/10 1/4 = 3/12 27/36 >
2/9 7/6 > 7/9
7/2 = 2/7 15/23 < 1 27/9 > 2 14/15 < 1 51/17 < 4
2x - 2/3 + 1/2x = -1
31/36 - (1/3 - x)2 = 5/6
`2x -2/3 +1/2x =-1`
`=> 2x+1/2x =-1+2/3`
`=> (2+1/2) x =-3/3 + 2/3`
`= 5/2 x = -1/3`
`=> x=-1/3 : 5/2`
`=>x= -2/15`
`31/36 - (1/3-x)^2 =5/6`
`=> (1/3-x)^2 = 31/36 - 5/6`
`=> (1/3-x)^2 =1/36`
`=> (1/3-x)^2 = (+-1/6)^2`
\(\Rightarrow\left[{}\begin{matrix}\dfrac{1}{3}-x=\dfrac{1}{6}\\\dfrac{1}{3}-x=-\dfrac{1}{6}\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{1}{6}\\x=\dfrac{1}{2}\end{matrix}\right.\)
Thực hiện phép tính: a,(9/10 - 15/16) X (5/12 - 11/15 - 7/20) b,(-1)3 + (-2/3)2: 2 2/3 + 5/6 c,15 X (-1/5)2 + 1/5 - 2 X (-1/2)3 - 1/2 d,22 - (-5/7) + (1/3)4 X 36
a, (\(\dfrac{9}{10}\) - \(\dfrac{15}{16}\)) \(\times\) ( \(\dfrac{5}{12}\) - \(\dfrac{11}{15}\) - \(\dfrac{7}{20}\))
= (\(\dfrac{72}{80}\) - \(\dfrac{75}{80}\)) \(\times\) (\(\)\(\dfrac{25}{60}\) - \(\dfrac{44}{60}\) - \(\dfrac{21}{60}\))
= - \(\dfrac{3}{80}\) \(\times\) (- \(\dfrac{2}{3}\))
= \(\dfrac{1}{40}\)
b, (-1)3 + (- \(\dfrac{2}{3}\))2 : 2\(\dfrac{2}{3}\) + \(\dfrac{5}{6}\)
= -13 + \(\dfrac{4}{9}\) : \(\dfrac{8}{3}\) + \(\dfrac{5}{6}\)
= -1 + \(\dfrac{4}{9}\) \(\times\) \(\dfrac{3}{8}\) + \(\dfrac{5}{6}\)
= -1 + \(\dfrac{1}{6}\) + \(\dfrac{5}{6}\)
= -1 + 1
= 0
c, 15 \(\times\) (- \(\dfrac{1}{5}\))2 + \(\dfrac{1}{5}\) - 2 \(\times\) (- \(\dfrac{1}{2}\))3 - \(\dfrac{1}{2}\)
= 15 \(\times\) \(\dfrac{1}{25}\) + \(\dfrac{1}{5}\) - 2 \(\times\) (- \(\dfrac{1}{8}\)) - \(\dfrac{1}{2}\)
= \(\dfrac{3}{5}\) + \(\dfrac{1}{5}\) + \(\dfrac{1}{4}\) - \(\dfrac{1}{2}\)
= \(\dfrac{4}{5}\) - \(\dfrac{1}{4}\)
= \(\dfrac{11}{20}\)
1:Tính :
a,1/2+7/8+7/19+42/47 b,3/2+6/5+17/8+36/27 c,3/5+(2/8+2/5+6/8) d,5 3/7+(2 5/21-1 2/3)