1)\(\dfrac{-3}{4}\)-x=0.25
2)x:4\(\dfrac{1}{3}\)=-2.5
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NL
19 tháng 2 2021
c) \(\dfrac{x-1}{5}+x=\dfrac{x+1}{7}\)
\(\Leftrightarrow\dfrac{7x-7}{35}+\dfrac{35x}{35}=\dfrac{5x+5}{35}\)
\(\Rightarrow7x-7+35x=5x+5\)
\(\Leftrightarrow7x+35x-5x=5+7\)
\(\Leftrightarrow37x=12\)
\(\Leftrightarrow x=\dfrac{12}{37}\)
Vậy pt có nghiệm duy nhất \(x=\dfrac{12}{37}\)
d) \(2\left(x-2,5\right)=0,25+\dfrac{4x-3}{8}\)
\(\Leftrightarrow\dfrac{16\left(x-2,5\right)}{8}=\dfrac{2}{8}+\dfrac{4x-3}{8}\)
\(\Rightarrow16x-40=2+4x-3\)
\(\Leftrightarrow16x-4x=2-3+40\)
\(\Leftrightarrow12x=39\)
\(\Leftrightarrow x=3,25\)
Vậy pt có nghiệm duy nhất \(x=3,25\)
8 tháng 7 2021
1) Ta có: \(\left(-\dfrac{2}{3}\right)^2\cdot\dfrac{-9}{8}-25\%\cdot\dfrac{-16}{5}\)
\(=\dfrac{4}{9}\cdot\dfrac{-9}{8}-\dfrac{1}{4}\cdot\dfrac{-16}{5}\)
\(=\dfrac{-1}{2}+\dfrac{4}{5}\)
\(=\dfrac{-5}{10}+\dfrac{8}{10}=\dfrac{3}{10}\)
2) Ta có: \(-1\dfrac{2}{5}\cdot75\%+\dfrac{-7}{5}\cdot25\%\)
\(=\dfrac{-7}{5}\cdot\dfrac{3}{4}+\dfrac{-7}{5}\cdot\dfrac{1}{4}\)
\(=\dfrac{-7}{5}\left(\dfrac{3}{4}+\dfrac{1}{4}\right)=-\dfrac{7}{5}\)
3) Ta có: \(-2\dfrac{3}{7}\cdot\left(-125\%\right)+\dfrac{-17}{7}\cdot25\%\)
\(=\dfrac{-17}{7}\cdot\dfrac{-5}{4}+\dfrac{-17}{7}\cdot\dfrac{1}{4}\)
\(=\dfrac{-17}{7}\cdot\left(\dfrac{-5}{4}+\dfrac{1}{4}\right)\)
\(=\dfrac{17}{7}\)
4) Ta có: \(\left(-2\right)^3\cdot\left(\dfrac{3}{4}\cdot0.25\right):\left(2\dfrac{1}{4}-1\dfrac{1}{6}\right)\)
\(=\left(-8\right)\cdot\left(\dfrac{3}{4}\cdot\dfrac{1}{4}\right):\left(\dfrac{9}{4}-\dfrac{7}{6}\right)\)
\(=\left(-8\right)\cdot\dfrac{3}{16}:\dfrac{54-28}{24}\)
\(=\dfrac{-3}{2}\cdot\dfrac{24}{26}\)
\(=\dfrac{-72}{52}=\dfrac{-18}{13}\)
18 tháng 2 2021
b) Ta có: \(3+\left(x-5\right)=2\left(3x-2\right)\)
\(\Leftrightarrow3+x-5=6x-4\)
\(\Leftrightarrow x-2-6x+4=0\)
\(\Leftrightarrow-5x+2=0\)
\(\Leftrightarrow-5x=-2\)
\(\Leftrightarrow x=\dfrac{2}{5}\)
Vậy: \(S=\left\{\dfrac{2}{5}\right\}\)
c) Ta có: \(2\left(x-0.5\right)+3=0.25\left(4x-1\right)\)
\(\Leftrightarrow2x-1+3=x-\dfrac{1}{4}\)
\(\Leftrightarrow2x+2-x+\dfrac{1}{4}=0\)
\(\Leftrightarrow x+\dfrac{9}{4}=0\)
\(\Leftrightarrow x=-\dfrac{9}{4}\)
Vậy: \(S=\left\{-\dfrac{9}{4}\right\}\)
d) Ta có: \(2\left(x-\dfrac{1}{4}\right)-4=-6\left(-\dfrac{1}{3}x+0.5\right)+2\)
\(\Leftrightarrow2x-\dfrac{1}{2}-4=2x-3+2\)
\(\Leftrightarrow2x-\dfrac{9}{2}=2x-1\)
\(\Leftrightarrow2x-2x=-1+\dfrac{9}{2}\)
\(\Leftrightarrow0x=\dfrac{7}{2}\)(vô lý)
Vậy: \(S=\varnothing\)
20 tháng 3 2017
a , \(\left(\dfrac{-2}{3}+1\dfrac{1}{4}-\dfrac{1}{6}\right):\dfrac{-24}{10}\)
=\(\left(\dfrac{-2}{3}+\dfrac{5}{4}-\dfrac{1}{6}\right):\dfrac{-12}{5}\)
=\(\left(\dfrac{-8}{12}+\dfrac{15}{12}-\dfrac{2}{12}\right)\cdot\dfrac{-5}{12}\)
=\(\dfrac{5}{12}\cdot\dfrac{-5}{12}=\dfrac{-25}{144}\)
b , \(\dfrac{13}{15}\cdot0,25\cdot3+\left(\dfrac{8}{15}-1\dfrac{19}{60}\right)1\dfrac{23}{24}\)
=\(\dfrac{13}{15}\cdot\dfrac{1}{4}\cdot3+\left(\dfrac{8}{15}-\dfrac{79}{60}\right)\cdot\dfrac{57}{24}\)
=\(\dfrac{13}{20}-\dfrac{47}{60}\cdot\dfrac{57}{24}\)
=\(\dfrac{13}{20}-\dfrac{893}{480}=\dfrac{312}{480}-\dfrac{893}{480}=\dfrac{-581}{480}\)
c , \(\left(\dfrac{12}{32}+\dfrac{5}{-20}-\dfrac{10}{24}\right):\dfrac{2}{3}\)
=\(\left(\dfrac{180}{480}-\dfrac{120}{480}-\dfrac{200}{480}\right)\cdot\dfrac{3}{2}\)
= \(\dfrac{-7}{24}\cdot\dfrac{3}{2}=\dfrac{-7}{16}\)
d , \(4\dfrac{1}{2}:\left(2,5-3\dfrac{3}{4}\right)+\left(-\dfrac{1}{2}\right)\)
=\(\dfrac{9}{2}:\left(\dfrac{5}{2}-\dfrac{15}{4}\right)-\dfrac{1}{2}\)
=\(\dfrac{9}{2}:\dfrac{-5}{4}-\dfrac{1}{2}=\dfrac{9}{2}\cdot\dfrac{-4}{5}-\dfrac{1}{2}=\dfrac{-18}{5}-\dfrac{1}{2}=\dfrac{-41}{10}\)
e , \(\dfrac{-5}{2}:\left(\dfrac{3}{4}-\dfrac{1}{2}\right)=\dfrac{-5}{2}\left(\dfrac{3}{4}-\dfrac{2}{4}\right)\)
=\(\dfrac{-5}{2}:\dfrac{1}{4}=\dfrac{-5}{2}\cdot4=-10\)
A
1
NH
23 tháng 3 2023
`25%+3/4+1/2:0,5-1/4:0,15+1/8:0,125`
`=1/4+3/4+1/2xx2-1/4xx4+1/8xx8`
`(1/4+3/4)+(1/2xx2)-(1/4xx4)+(1/8xx8)`
`=1+1-1+1`
`=2`
8 tháng 11 2018
câu 1 \(A=\dfrac{3^2}{5^2}.5^2-\dfrac{9^3}{4^3}:\dfrac{3^3}{4^3}+\dfrac{1}{2}\)
\(A=\dfrac{3^2}{5^2}.5^2-\dfrac{\left(3^2\right)^3}{4^3}.\dfrac{4^3}{3^3}+\dfrac{1}{2}\)
\(A=\dfrac{3^2}{5^2}.5^2-\dfrac{3^6}{4^3}.\dfrac{4^3}{3^3}+\dfrac{1}{2}=3^2-3^3+\dfrac{1}{2}=-18+\dfrac{1}{2}=-\dfrac{35}{2}\)
\(B=\left[\dfrac{4}{11}+\dfrac{7}{22}.2\right]^{2010}-\left(\dfrac{1}{2^2}.\dfrac{4^4}{8^2}\right)^{2009}\)
\(B=\left[\dfrac{4}{11}+\dfrac{7}{11}\right]^{2010}-\left(\dfrac{1}{2^2}.\dfrac{\left(2^2\right)^4}{\left(2^3\right)^2}\right)^{2009}\)
\(B=1^{2010}-\left(\dfrac{1}{2^2}.\dfrac{2^8}{2^6}\right)^{2009}\)
\(B=1^{2010}-\left(\dfrac{2^8}{2^8}\right)^{2009}\)
\(B=1^{2010}-1^{2009}=1-1=0\)
8 tháng 11 2018
câu 2
a) \(2x-\dfrac{5}{4}=\dfrac{20}{15}\)
\(\Leftrightarrow2x=\dfrac{4}{3}+\dfrac{5}{4}\)
\(\Leftrightarrow2x=\dfrac{31}{12}\)
\(\Leftrightarrow x=\dfrac{31}{24}\)
b) \(\left(x+\dfrac{1}{3}\right)^3=\left(-\dfrac{1}{2}\right)^3\)
\(\Leftrightarrow x+\dfrac{1}{3}=-\dfrac{1}{2}\)
\(\Leftrightarrow x=-\dfrac{1}{2}-\dfrac{1}{3}\)
\(\Leftrightarrow x=-\dfrac{5}{6}\)
TT
1
BT
23 tháng 2 2018
Ta có: \(A=\left(0,25\right)^{-1}.\dfrac{1}{4}^{-2}.\dfrac{4}{3}^{-2}.\dfrac{5}{4}^{-1}.\dfrac{2}{3}^{-3}\)
--> A= \(\left(\dfrac{\dfrac{1}{1}}{4}\right).\left(\dfrac{\dfrac{1}{1}}{4^2}\right).\left(\dfrac{\dfrac{1}{4^2}}{3^2}\right).\left(\dfrac{\dfrac{1}{5}}{4}\right).\left(\dfrac{\dfrac{1}{2^3}}{3^3}\right)\)
--> A= 4.42. \(\dfrac{3^2}{4^2}\).\(\dfrac{4}{5}\) . \(\dfrac{3^3}{2^3}\)
--> A= \(\dfrac{4.4^2.3^2.3^3}{4^{2.}.5.2^3}=\dfrac{2.3^5}{5}=\dfrac{2.243}{5}\)
--> A= 97,2
tớ sẽ ko làm cách chuyển vế đâu nha!
mong thông cảm
câu 1:
x = -3/4 - 25/100
x = -1
câu 2:
x = -25/10 . 13/3
x = -65/6