Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
a: =>(2x+1/2)^2=1/4
=>2x+1/2=1/2 hoặc 2x+1/2=-1/2
=>x=-1/2 hoặc x=0
b: =>(x-1/5)^2=49
=>x-1/5=7 hoặc x-1/5=-7
=>x=-6,8 hoặc x=7,2
c: =>1,2x=12
=>x=10
d: =>3/4x+1/2x+1/2=-11/4
=>5/4x=-11/4-2/4=-13/4
=>x=-13/5
e: =>-0,25x+1,25x=0,2
=>x=0,2
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: \(\left(-2\right)^3\cdot\left(\dfrac{3}{4}\cdot0.25\right):\left(2\dfrac{1}{4}-1\dfrac{1}{6}\right)\)
\(=\left(-8\right)\cdot\left(\dfrac{3}{4}\cdot\dfrac{1}{4}\right):\left(\dfrac{9}{4}-\dfrac{7}{6}\right)\)
\(=\left(-8\right)\cdot\dfrac{3}{16}:\dfrac{54-28}{24}\)
\(=\dfrac{-3}{2}\cdot\dfrac{24}{26}\)
\(=\dfrac{-72}{52}=\dfrac{-18}{13}\)
0,25 × X - 27/8 × X = 3/4
X × ( 0,25 - 27/8 ) = 0,75
X × ( -25/8 ) = 0,75
X = 0,75 ÷ ( -25/8 )
X = -6/25
a) \(\frac{x}{5}=\frac{x}{-1}\)
\(\Leftrightarrow\) -x = 5x
\(\Leftrightarrow\) -x - 5x = 0
\(\Leftrightarrow\) -6x = 0
\(\Leftrightarrow\) x = 0
b) \(\frac{3\left(x-1\right)}{-5}\) = \(\frac{4\left(x+2\right)}{6}\)
\(\Leftrightarrow\) \(\frac{-18\left(x-1\right)}{30}\) = \(\frac{-20\left(x+2\right)}{30}\)
\(\Leftrightarrow\) -18(x - 1) = -20(x +2)
\(\Leftrightarrow\) -18x + 18 = -20x - 40
\(\Leftrightarrow\) -18x + 20x = -40 - 18
\(\Leftrightarrow\) 2x = -58
\(\Leftrightarrow\) x = -29
c) \(\frac{7-2x}{3}\) = \(\frac{0,75-5}{4}\)
\(\Leftrightarrow\) (7 - 2x).4 = (0,75 - 5).3
\(\Leftrightarrow\) 28 - 8x = 2,25 - 15
\(\Leftrightarrow\) -8x = -2,25 - 15 - 28 = -40,75
\(\Leftrightarrow\) x = \(\frac{163}{32}\)
(0.25-0.3x)x1/3-1/4=-5/16
(0.25-0.3x)x1/3=-1/16 (làm tắt)
0.25-0.3x=-1/16:1/3
0.25-0.3x=-3/16
0.3x=0.4375 =>x=35/24
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
0,75 x 4 - X = 0,25 : 1/8
3 - X = 2
X = 3-2
X = 1
TL:
\(0,75\times4-x=0,25:\dfrac{1}{8}\)
\(\Rightarrow3-x=0,25:0,125\)
\(\Rightarrow3-x=2 \)
\(\Rightarrow x=1\)
Vậy x=1
HT!