tìm x biết : x : 4\(\frac{1}{3}\)= -2,5
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Đoạn đó ( dưới ) :
\(\Rightarrow\left[\begin{array}{nghiempt}\frac{1}{4}x=2\\\frac{1}{4}x=-2\end{array}\right.\)\(\Rightarrow\left[\begin{array}{nghiempt}x=8\\x=-8\end{array}\right.\)
:)
Giải :
\(\frac{1}{4}\left|x\right|-2,5=-\frac{1}{2}\)
\(\Rightarrow\frac{1}{4}\left|x\right|=2\)
\(\Rightarrow\left[\begin{array}{nghiempt}\frac{1}{4}.x=2\\\frac{1}{4}.x=-2\end{cases}\Rightarrow\left[\begin{array}{nghiempt}x=8\\x=-8\end{array}\right.}\)
\(a,\frac{3}{4}+\frac{1}{4}:x=\frac{2}{5}\)
\(\Leftrightarrow\frac{1}{4}:x=\frac{2}{5}-\frac{3}{4}\)
\(\Leftrightarrow\frac{1}{4}:x=\frac{8}{20}-\frac{15}{20}\)
\(\Leftrightarrow\frac{1}{4}:x=\frac{-7}{20}\)
\(\Leftrightarrow x=\frac{1}{4}.\frac{20}{-7}\)
\(\Leftrightarrow x=\frac{20}{-28}\)
\(b,|x-2,5|=1,5\)
\(\Leftrightarrow\orbr{\begin{cases}x-2,5=1,5\\x-2,5=-1,5\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=1,5+2,5\\x=-1,5+2,5\end{cases}}\)
\(\Leftrightarrow\orbr{\begin{cases}x=3\\x=1\end{cases}}\)
a) vì /x/>= 0 => x = { 2,5 ; -2,5 }
b) ko tìm đươc x thỏa mãn vì /x/ >= 0
c) /x/ = 2 + 0,573
<=> /x/ = 2,573
<=> x = { 2,573 ; -2,573 }
d) /x+ 1/3 / = -1+(-4 )
<=> /x+1/3 /= -5
vì /x+1/3 / luôn lớn hơn hoặc bằng 0 => ko tìm được x thỏa mãn
\(\left(x-3,5\right):3\frac{1}{2}=-1\frac{3}{4}+2,5\)
\(\left(x-3,5\right):3\frac{1}{2}=0,75\)
\(x-3,5=0,75x3\frac{1}{2}\)
\(x=\frac{21}{8}+3,5\)
\(x=6,125\)
= \(\left(x-3,5\right):\frac{7}{2}-2,5=\frac{-7}{4}\)
=> \(\left(x-3,5\right):\frac{7}{2}=\frac{-7}{4}+2,5=0,75\)
=> \(x-3,5=0,75x\frac{7}{2}=2,625\)
=> x= 2,625 + 3,5
x = 6,125
a ) \(\left(\frac{2}{5}-x\right):1\frac{1}{3}+\frac{1}{2}=-4\)
\(\left(\frac{2}{5}-x\right):\frac{4}{3}+\frac{1}{2}=-4\)
\(\left(\frac{2}{5}-x\right):\frac{4}{3}=-4-\frac{1}{2}\)
\(\left(\frac{2}{5}-x\right):\frac{4}{3}=-\frac{9}{2}\)
\(\frac{2}{5}-x=-\frac{9}{2}.\frac{4}{3}\)
\(\frac{2}{5}-x=-3\)
\(x=\frac{2}{5}-\left(-3\right)\)
\(x=\frac{2}{5}+3\)
\(x=\frac{3}{5}-\frac{15}{5}\)
\(x=-\frac{12}{5}\)
Vay \(x=-\frac{12}{5}\)
b ) \(\left(-3+\frac{3}{x}-\frac{1}{3}\right):\left(1+\frac{2}{5}+\frac{2}{3}\right)=-\frac{5}{4}\)
\(\left(-3+\frac{3}{x}-\frac{1}{3}\right):\left(\frac{15}{15}+\frac{6}{15}+\frac{10}{15}\right)=-\frac{5}{4}\)
\(\left(-3+\frac{3}{x}-\frac{1}{3}\right):\left(\frac{15+6+10}{15}\right)=-\frac{5}{4}\)
\(\left(-3+\frac{3}{x}-\frac{1}{3}\right):\frac{31}{15}=-\frac{5}{4}\)
\(\left(-3+\frac{3}{x}-\frac{1}{3}\right)=-\frac{5}{4}.\frac{31}{15}\)
\(\left(-3+\frac{3}{x}-\frac{1}{3}\right)=-\frac{1}{4}.\frac{31}{3}\)
\(-3+\frac{3}{x}-\frac{1}{3}=-\frac{31}{12}\)
\(-3+\frac{3}{x}=-\frac{31}{12}+\frac{1}{2}\)
\(-3+\frac{3}{x}=-\frac{31}{12}+\frac{6}{12}\)
\(-3+\frac{3}{x}=\frac{-25}{12}\)
\(\frac{3}{x}=\frac{-25}{12}+3\)
\(\frac{3}{x}=\frac{-25}{12}+\frac{36}{12}\)
\(\frac{3}{x}=\frac{5}{6}\)
\(\frac{18}{6x}=\frac{5x}{6x}\)
Đèn dây , bạn tự làm tiếp nhé , de rồi chứ
a. |x| = 2,5
=> \(x\in\left\{-2,5;2,5\right\}\).
b. |x| = -1,2
Mà |x| > 0 ( theo lí thuyết )
Vậy không tồn tại x thỏa mãn.
c. |x|+0,573=2
=> |x|=2-0,573
=> |x|=1,427
=> \(x\in\left\{-1,427;1,427\right\}\).
d. |x+1/3|-4=-1
=> |x+1/3|=-1+4
=> |x+1/3|=3
+) x+1/3=3
=> x=3-1/3
=> x=8/3
+) x+1/3=-3
=> x=-3-1/3
=> x=-10/3
Vậy \(x\in\left\{-\frac{10}{3};\frac{8}{3}\right\}\).
\(x:4\frac{1}{3}=-2,5\) \(x:\frac{-3}{5}=\frac{-10}{21}\)
\(\Rightarrow x:\frac{13}{3}=\frac{-25}{10}\) \(\Rightarrow x=\frac{-10}{21}.\frac{-3}{5}\)
\(\Rightarrow x=\frac{-5}{2}.\frac{13}{3}\) \(\Rightarrow x=\frac{2}{7}\)
\(\Rightarrow x=\frac{-65}{6}\)
c)\(\frac{2}{3}x-\frac{1}{2}=\frac{1}{10}\) \(\frac{1}{2}x+\frac{1}{2}=\frac{5}{2}\)
\(\Rightarrow\frac{2}{3}x=\frac{1}{10}+\frac{1}{2}\) \(\Rightarrow\frac{1}{2}x=\frac{5}{2}-\frac{1}{2}\)
\(\Rightarrow\frac{2}{3}x=\frac{1}{10}+\frac{5}{10}\) \(\Rightarrow\frac{1}{2}x=\frac{4}{2}\)
\(\Rightarrow\frac{2}{3}x=\frac{6}{10}\) \(\Rightarrow x=\frac{4}{2}:\frac{1}{2}\Rightarrow2.2=4\)
\(\Rightarrow x=\frac{6}{10}:\frac{2}{3}\Rightarrow\frac{3}{5}.\frac{3}{2}=\frac{9}{10}\)
(15/4.4-12/5.5/4)-(7/2:5/2-1/5)-1/5.x=51/5
(15-3)-(7/5-1/5)-1/5.x=51/5
12-6/5-1/5.x=51/5
54/5-1/5.x=51/5
1/5x=54/5-51/5
1/5x=3/5
x=3
1)\(\frac{x+1}{2}+\frac{x+1}{3}+\frac{x+1}{4}=\frac{x+1}{5}+\frac{x+1}{6}\)
\(\Leftrightarrow\frac{x+1}{2}+\frac{x+1}{3}+\frac{x+1}{4}-\frac{x+1}{5}-\frac{x+1}{6}=0\)
\(\Leftrightarrow\left(x+1\right)\left(\frac{1}{2}+\frac{1}{3}+\frac{1}{4}-\frac{1}{5}-\frac{1}{6}\right)=0\)
\(\Leftrightarrow\left(x+1\right)=0\).Do \(\frac{1}{2}+\frac{1}{3}+\frac{1}{4}-\frac{1}{5}-\frac{1}{6}\ne0\)
\(\Leftrightarrow x=-1\)
\(x:4\frac{1}{3}=-2,5\)
\(x:\frac{13}{3}=\frac{-25}{10}\)
\(x=\frac{-25}{10}.\frac{13}{3}\)
\(x=\frac{-65}{6}\)
k nha
x: 4 1/3 = -2,5
x: 13/3 = -5/2
x = -5/2 : 13/3
x = -5/2 . 3/13
x = -15/26