bài 1:Thực hiện phép tinh
a, x+ 5 = 2015 - (12 -7)
b, -7|x+3| = -49
c, (105 - x) : 25 = 20150 + 1
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Bài 2:
a: =>x-35=-23
=>x=12
b: =>|x-8|=13
=>x-8=13 hoặc x-8=-13
=>x=21 hoặc x=-5
Bài 1:
a: =42-98-42+12-12=-98
b: =10x4x3x(-25)=40x(-25)x3=-1000x3=-3000
bài 7:a thực hiện phép tính .81 x 2022 + 25 x 2022 - 6 x 2022 .B Tìm x biết ( x - 1 ) 2/3 - 1/5= 2/5
\(a,81\cdot2022+25\cdot2022-6\cdot2022=2022\cdot\left(81+25-6\right)=2022\cdot100=202200\)
\(b,\left(x-1\right)\cdot\frac{2}{3}-\frac{1}{5}=\frac{2}{5}\)
\(\left(x-1\right)\cdot\frac{2}{3}=\frac{3}{5}\)
\(x-1=\frac{9}{10}\)
\(x=\frac{19}{10}\)
Vậy \(x=\frac{19}{10}\)
( Nếu phần b là hỗn số thì mình làm thế kia , còn nếu là nhân thì bạn tham khảo Câu hỏi của lương bảo ngọc - Toán lớp 5 - Học trực tuyến OLM nhé )
81 x 2022 + 25 x 2022 - 6 x 2022
= ( 81 + 25 - 6 ) x 2022
= 100 x 2022
= 202 200
b) \(\left(\text{x - 1}\right)\frac{\text{2}}{\text{3}}-\frac{\text{1}}{\text{5}}=\frac{\text{2}}{\text{5}}\)
\(\frac{\text{3 x }\text{( x - 1 ) }+\text{2}}{\text{3}}=\frac{\text{1}}{\text{5}}+\frac{\text{2}}{\text{5}}=\frac{\text{3}}{\text{5}}\)
=> \(\text{3 x ( x - 1 ) }+\text{2}=\frac{\text{3}}{\text{5}}\text{ x 3 = }\frac{\text{9}}{\text{5}}\)
=> \(\text{3 x ( x - 1 ) }=\frac{\text{9}}{\text{5}}-\text{2}=\frac{\text{-1}}{\text{5}}\)
=> \(\text{ x-1}=\frac{\text{-1}}{\text{5}}:3=\frac{\text{-1}}{\text{15}}\)
=> \(\text{x}=\frac{\text{-1}}{\text{15}}+\text{1 = }\frac{\text{14}}{\text{15}}\)
\(a,\left(\frac{3}{8}+-\frac{3}{4}+\frac{7}{12}\right):\frac{5}{6}+\frac{1}{2}\)
= \(\left(-\frac{3}{8}+\frac{7}{12}\right):\frac{5}{6}+\frac{1}{2}\)
= \(\frac{5}{24}:\frac{5}{6}+\frac{1}{2}\)
= \(\frac{1}{4}+\frac{1}{2}\)
= \(\frac{3}{4}\)
b)\(-\frac{7}{3}.\frac{5}{9}+\frac{4}{9}.\left(-\frac{3}{7}\right)+\frac{17}{7}\)
=\(-\frac{35}{27}+\left(-\frac{4}{21}\right)+\frac{17}{7}\)
= \(-\frac{35}{27}+\frac{47}{21}\)
= \(\frac{178}{189}\)
c) \(\frac{117}{13}-\left(\frac{2}{5}+\frac{57}{13}\right)\)
= \(\frac{117}{13}-\frac{311}{65}\)
= \(\frac{274}{65}\)
d) \(\frac{2}{3}-0,25:\frac{3}{4}+\frac{5}{8}.4\)
= \(\frac{2}{3}-\frac{1}{4}:\frac{3}{4}+\frac{5}{8}.4\)
= \(\frac{2}{3}-\frac{1}{3}+\frac{5}{2}\)
= \(\frac{1}{3}+\frac{5}{2}\)
= \(\frac{17}{6}\)
Bài 1 :
\(a)\frac{-17}{30}-\frac{11}{-15}+\left(-\frac{7}{12}\right)\)
\(=\frac{1}{6}+\left(-\frac{7}{12}\right)\)
\(=-\frac{5}{12}\)
\(b)-\frac{5}{9}+\frac{5}{9}:\left(1\frac{2}{3}-2\frac{1}{12}\right)\)
\(=-\frac{5}{9}+\frac{5}{9}:\left(\frac{5}{3}-\frac{25}{12}\right)\)
\(=-\frac{5}{9}+\frac{5}{9}:\left(-\frac{5}{12}\right)\)
\(=-\frac{5}{9}+\left(-\frac{2}{3}\right)\)
\(=-\frac{1}{9}\)
\(c)-\frac{7}{25}\times\frac{11}{13}+\left(-\frac{7}{25}\right)\times\frac{2}{13}-\frac{18}{25}\)
\(=-\frac{77}{325}+\left(-\frac{14}{325}\right)-\frac{18}{25}\)
\(=-\frac{7}{25}-\frac{18}{25}\)
\(=-1\)
Bài 1:
a, 58.32 + 58.68 - 800
= 58.(32 + 68) - 800
= 58.100 - 800
= 5800 - 800
= 5000
b, 12020 + 280 : [55 - (7 - 4)3]
= 12020 + 280 : [ 55 - 33 ]
= 12020 + 280 : [ 28]
= 12020 + 10
= 12030
c, (96 - 19 - 45) - (55 + 96 - 119)
= 96 - 19 - 45 - 55 - 96 + 119
= (96 - 96) + (119 - 19) - (45 + 55)
= 0 + 100 - 100
= 0
\(\frac{4}{5}\)+ \(\frac{1}{5}\): \(\frac{-2}{15}\)= \(\frac{4}{5}\)+ \(\frac{1}{5}\)* \(\frac{-15}{2}\)=\(\frac{4}{5}\) + \(\frac{-3}{2}\)= \(\frac{-7}{10}\)
b = \(\frac{-7}{12}\). (\(\frac{3}{11}\)+ \(\frac{-14}{11}\)) + \(\frac{5}{6}\)= \(\frac{-7}{12}\). (-1) + \(\frac{5}{6}\)= \(\frac{7}{12}\)+ \(\frac{10}{12}\)= \(\frac{17}{12}\)
a) \(x+5=2015-\left(12-7\right)\)
\(\Leftrightarrow x+5=2015-5\)\(\Leftrightarrow x+5=2010\)
\(\Leftrightarrow x=2005\)
Vậy \(x=2005\)
b) \(-7\left|x+3\right|=-49\)\(\Leftrightarrow\left|x+3\right|=7\)
\(\Leftrightarrow\orbr{\begin{cases}x+3=-7\\x+3=7\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=-10\\x=4\end{cases}}\)
Vậy \(x=-10\)hoặc \(x=4\)
c) \(\left(105-x\right):2^5=2015^0+1\)
\(\Leftrightarrow\left(105-x\right):32=1+1\)\(\Leftrightarrow\left(105-x\right):32=2\)
\(\Leftrightarrow105-x=64\)\(\Leftrightarrow x=41\)
Vậy \(x=41\)
a. x+5 = 2015-(12-7)
x+5= 2015-5
x+5 = 2010
x=2005
b, -7/ x+3/ =-49
/x+3/ = 7
x+3 = 7 suy ra x=4
hoặc x+3= -7 suy ra x=-10
c. (105-x) : 2^5= 2015^0 + 1
(105-x) : 32= 1+1
(105-x) : 32= 2
105-x= 64
x= 41
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