0,5x-\(\frac{2}{5}\)x=\(\frac{5}{12}\)
giải giúp mih huhu
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\(\left(x+\frac{1}{2}\right)^4=\frac{1}{16}\)
=>\(\left(x+\frac{1}{2}\right)^4=\frac{+}{-}\left(\frac{1}{2}\right)^4\)
=> \(x+\frac{1}{2}=\frac{+}{-}\frac{1}{2}\)
còn đâu bạn tự giải nốt nha, chỗ \(\frac{+}{-}\)là cộng trừ đó nha
PT <=> \(\frac{-5x+9}{9}=\frac{6x-90}{9}\)
=> -5x + 9 = 6x - 90
<=> -5x - 6x = -90 - 9
<=> -11x = -99
<=> x = 9
Vậy S = {9}.
\(\hept{\begin{cases}\text{|}0,5x\text{|}=0,5x\\\sqrt{\left(0,5x\right)^2}=0,5x\\\left(0,5x\right)^2=\left(0,5x\right)^2\end{cases}}\)
2, tương tự
\(\hept{\begin{cases}\text{|}-\frac{2}{3}x\text{|}=\frac{2}{3}x\\\sqrt{\left(-\frac{2}{3}x\right)^2}=\frac{2}{3}x\\\left(-\frac{2}{3}x\right)^2=\left(\frac{2}{3}x\right)^2\end{cases}}\)
4, tương tự
a) \(\frac{3x+2}{-4x+5}=-\frac{4}{3}\left(ĐKXĐ:x\ne\frac{5}{4}\right)\)
\(\Rightarrow3\left(3x+2\right)=-4\left(-4x+5\right)\)
\(\Leftrightarrow9x+6=16x-20\)
\(\Leftrightarrow7x=26\)
\(\Leftrightarrow x=\frac{26}{7}\)
b) \(\frac{2\left|x\right|+5}{-4x+3}=-\frac{5}{4}\)(Thôi bài sau tự tìm đkxđ nhá)
\(\Rightarrow8\left|x\right|+20=20x-15\)
\(\Leftrightarrow8\left|x\right|-20x+35\)\(\left(1\right)\)
TH1: Nếu \(x\ge0\)thì \(\left(1\right)\Leftrightarrow8x-20x+35=0\Leftrightarrow x=\frac{35}{12}\left(tm\right)\)
TH2: Nếu \(x< 0\)thì \(\left(1\right)\Leftrightarrow-8x-20x+35=0\Leftrightarrow x=\frac{35}{28}\left(ktm\right)\)
Vậy x=35/12
c)\(\frac{2x+1}{5}=\frac{3}{2x-1}\)
\(\Rightarrow4x^2-1=15\)
\(\Leftrightarrow4x^2=16\)
\(\Leftrightarrow x^2=4\)
\(\Leftrightarrow\orbr{\begin{cases}x=2\\x=-2\end{cases}}\)
d)\(\frac{x+1}{2x+1}=\frac{0,5x+2}{x+3}\)
\(\Leftrightarrow\left(x+1\right)\left(x+3\right)=\left(2x+1\right)\left(0,5x+2\right)\)
\(\Leftrightarrow x^2+4x+3=x^2+4,5x+2\)
\(\Leftrightarrow0,5x=1\)
\(\Leftrightarrow x=2\)
e) \(\frac{\left|6x+1\right|}{4}=\frac{2}{4}\)
\(\Leftrightarrow\left|6x+1\right|=2\)
\(\Leftrightarrow\orbr{\begin{cases}6x+1=2\\6x+1=-2\end{cases}\Leftrightarrow\orbr{\begin{cases}x=\frac{1}{6}\\x=-\frac{1}{2}\end{cases}}}\)
g)\(\frac{\left|3x-5\right|}{3}=\frac{\left|x\right|}{2}\)
\(\Leftrightarrow\frac{\left|3x-5\right|}{\left|x\right|}=\frac{3}{4}\)
\(\Leftrightarrow\left|\frac{3x-5}{x}\right|=\frac{3}{4}\)
\(\Leftrightarrow\orbr{\begin{cases}\frac{3x-5}{x}=\frac{3}{4}\\\frac{3x-5}{x}=-\frac{3}{4}\end{cases}\Leftrightarrow\orbr{\begin{cases}x=\frac{20}{9}\\x=\frac{4}{3}\end{cases}}}\)
Mỏi tay quá, xin tý cho sảng khoái nào!!
\(\)
a, Đề có vẻ sai sai nhé :v
b, \(\left|\frac{1}{2}x-\frac{2}{3}\right|-1=\frac{1}{6}\)
\(\Leftrightarrow\left|\frac{1}{2}x-\frac{2}{3}\right|=\frac{7}{6}\)
\(\Leftrightarrow\orbr{\begin{cases}\frac{1}{2}x-\frac{2}{3}=\frac{7}{6}\\\frac{1}{2}x-\frac{2}{3}=-\frac{7}{6}\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=\frac{11}{3}\\x=-1\end{cases}}\)
Vậy : ....
c, \(\frac{2}{6}+\frac{2}{12}+\frac{2}{20}+...+\frac{2}{x(x+1)}=\frac{4}{5}\)
\(\Leftrightarrow\frac{2}{2\cdot3}+\frac{2}{3\cdot4}+\frac{2}{4\cdot5}+...+\frac{2}{x\cdot(x+1)}=\frac{4}{5}\)
\(\Leftrightarrow2\left[\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{x}-\frac{1}{x+1}\right]=\frac{4}{5}\)
\(\Leftrightarrow2\left[\frac{1}{2}-\frac{1}{x+1}\right]=\frac{4}{5}\)
\(\Leftrightarrow\frac{1}{2}-\frac{1}{x+1}=\frac{2}{5}\)
\(\Leftrightarrow\frac{1}{x+1}=\frac{1}{10}\)
\(\Leftrightarrow x+1=10\Leftrightarrow x=9\)
Vậy x = 9
\(\frac{x+7}{3}+\frac{x+5}{4}=\frac{x+3}{5}+\frac{x+1}{6}\)
\(\Rightarrow\frac{x+7}{3}+2+\frac{x+5}{4}+2=\frac{x+3}{5}+2+\frac{x+1}{6}+2\)
\(\Rightarrow\frac{x+13}{3}+\frac{x+13}{4}=\frac{x+13}{5}+\frac{x+13}{6}\)
\(\Rightarrow\frac{x+13}{3}+\frac{x+13}{4}-\frac{x+13}{5}-\frac{x+13}{6}=0\)
\(\Rightarrow\left(x+13\right)\left(\frac{1}{3}+\frac{1}{4}-\frac{1}{5}-\frac{1}{6}\right)=0\)
Vì \(\left(\frac{1}{3}>\frac{1}{4}>\frac{1}{5}>\frac{1}{6}\right)\Rightarrow\)\(\left(\frac{1}{3}+\frac{1}{4}-\frac{1}{5}-\frac{1}{6}\right)>0\)
\(\Rightarrow x+13=0\Leftrightarrow x=-13\)
\(\frac{x+m}{n+p}+\frac{x+n}{p+m}+\frac{x+p}{n+m}+3=0\)
\(\Rightarrow\frac{x+m}{n+p}+1+\frac{x+n}{p+m}+1+\frac{x+p}{n+m}+1=0\)
\(\Rightarrow\frac{x+m+n+p}{n+p}+\frac{x+m+n+p}{p+m}+\frac{x+m+n+p}{n+m}=0\)
\(\Rightarrow\left(x+m+n+p\right)\left(\frac{1}{n+p}+\frac{1}{p+m}+\frac{1}{n+m}\right)=0\)
Vì m,n,p là số dương nên \(\left(\frac{1}{n+p}+\frac{1}{p+m}+\frac{1}{n+m}\right)>0\)
\(\Rightarrow x+m+n+p=0\Rightarrow x=-\left(m+n+p\right)\)
\(\frac{5x+\frac{3x-4}{5}}{15}=\frac{\frac{3-x}{15}+7x}{5}+1-x\)
\(\Rightarrow\frac{\frac{25x+3x-4}{5}}{15}=\frac{\frac{3-x+105x}{15}}{5}+1-x\)
\(\Rightarrow\frac{\frac{28x-4}{5}}{15}=\frac{\frac{3+104x}{15}}{5}+1-x\)
\(\Rightarrow\frac{28x-4}{75}=\frac{3+104x}{75}+1-x\)
\(\Rightarrow\frac{28x-4}{75}=\frac{3+104x+75-75x}{75}\)
\(\Rightarrow\frac{28x-4}{75}=\frac{78+29x}{75}\)
\(\Rightarrow28x-4=78+29x\)
\(\Rightarrow x=-82\)
\(\left(0,5-\frac{2}{5}\right)\cdot x=\frac{5}{12}\)
\(\left(\frac{1}{2}-\frac{2}{5}\right)\cdot x=\frac{5}{12}\)
\(\frac{1}{10}\cdot x=\frac{5}{12}\)
\(x=\frac{5}{12}:\frac{1}{10}\)
\(x=\frac{5}{12}.\frac{10}{1}\)
\(x=\frac{25}{6}\)
( mình ko pik mk tính đúng ko nhưng cách làm đúng rồi đó )
\(0,5x-\frac{2}{5}x=\frac{5}{12}\)
\(x\left(0,5+\frac{2}{5}\right)=\frac{5}{12}\)
\(\frac{9}{10}x=\frac{5}{12}\)
x=\(\frac{5}{12}:\frac{9}{10}\)
x=\(\frac{25}{54}\)