(2.x-1)^2=25
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31 tháng 5 2023
a: TH1: x>=2
A=x+x-2=2x-2
TH2: x<2
A=x+2-x=2
b: TH1: x>=3
A=x-3-x=-3
TH2: x<3
A=3-x-x=-2x+3
c: TH1: x>=1
C=x-x+1=1
TH2: x<1
C=x+x-1=2x-1
d: TH1: m>=3
C=m-3-2m=-3-m
TH2: m<3
C=-m+3-2m=-3m+3
e: TH1: m>=1
E=m-m+1=1
TH2: m<1
E=m+m-1=2m-1
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: \(\left(-2\right)^3\cdot\left(\dfrac{3}{4}\cdot0.25\right):\left(2\dfrac{1}{4}-1\dfrac{1}{6}\right)\)
\(=\left(-8\right)\cdot\left(\dfrac{3}{4}\cdot\dfrac{1}{4}\right):\left(\dfrac{9}{4}-\dfrac{7}{6}\right)\)
\(=\left(-8\right)\cdot\dfrac{3}{16}:\dfrac{54-28}{24}\)
\(=\dfrac{-3}{2}\cdot\dfrac{24}{26}\)
\(=\dfrac{-72}{52}=\dfrac{-18}{13}\)
KN
1
NN
23 tháng 12 2023
Bài 1
a, -25 . 63 - 25 . 3
= 25 . (-63) - 25 . 3
= 25 . [(-63) - 3]
= 25 . (-66) = -1650
Bài 2
c, (x + 1)2 = 16
=> (x + 1)2 = 42
=> x + 1 = 4
=> x = 3
d, (-38) - (x - 2) = -16
=> (x - 2) = -38 - (-16)
=> x - 2 = -38 + 16 = -22
=> x = 2 + (-22)
=> x = -20
20 tháng 12 2022
a: =25(15+45*3)
=25*150
=3750
b: \(=-10\left(25+75-50\right)=-10\cdot50=-500\)
c: =>3^x-2=27
=>x-2=3
=>x=5
d: =>2x-5=-4
=>2x=1
=>x=1/2
e: =>2(x-1)^2=32
=>(x-1)^2=16
=>x-1=4 hoặc x-1=-4
=>x=-3 hoặc x=5
f: =>25(x+3)=75
=>x+3=3
=>x=0
NC
3
10 tháng 5 2022
1: \(\left(3x-\dfrac{1}{5}\right)^2=\left(-\dfrac{3}{25}\right)^2\)
=>3x-1/5=3/25 hoặc 3x-1/5=-3/25
=>3x=8/25 hoặc 3x=2/25
=>x=8/75 hoặc x=2/75
2: \(\left(2x-\dfrac{1}{3}\right)^2=\left(-\dfrac{2}{9}\right)^2\)
=>2x-1/3=2/9 hoặc 2x-1/3=-2/9
=>2x=5/9 hoặc 2x=1/9
=>x=5/18 hoặc x=1/18
NA
1
10 tháng 5 2022
1.\(\left(\dfrac{1}{3}-x\right)^2=\dfrac{9}{25}\Leftrightarrow\left[{}\begin{matrix}\dfrac{1}{3}-x=\dfrac{3}{5}\\\dfrac{1}{3}-x=-\dfrac{3}{5}\end{matrix}\right.\) \(\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{4}{15}\\x=\dfrac{14}{15}\end{matrix}\right.\)
2.\(\left(5-x\right)^2=25\Leftrightarrow\left[{}\begin{matrix}5-x=5\\5-x=-5\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\x=10\end{matrix}\right.\)
NT
2
S
10 tháng 2 2020
\(x+\left(x+1\right)+\left(x+2\right)+....+13+14=14\Leftrightarrow x+\left(x+1\right)+....+13\Leftrightarrow x=-13\)
\(25+24+23+....+x+\left(x-1\right)+\left(x-2\right)=25\Leftrightarrow24+....+\left(x-2\right)=0\Leftrightarrow x-2=-24\)
\(\Leftrightarrow x=-22\)
\((2x-1)^2=25\)
\((2x-1)^2=5^2\) hoặc \((2x-1)^2=(-5)^2\)
\(2x-1=5\) hoặc \(2x-1=-5\)
\(@TH1:2x-1=5=>2x=6=>x=3\)
\(@TH2:2x-1=-5=>2x=-4=>x=-2\)
( 2x - 1 ) 2 = 25
( 2x - 1 ) 2 = 52
2x - 1 = 5
2x = 6
x = 3