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\(\left(\frac{2}{3}+x\right)\left(\frac{1}{5}-2x\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}\frac{2}{3}+x=0\\\frac{1}{5}-2x=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=-\frac{2}{3}\\-2x=-\frac{1}{5}\end{cases}\Leftrightarrow}}\orbr{\begin{cases}x=-\frac{2}{3}\\x=\frac{1}{10}\end{cases}}\)
Vậy:.......
#H
\(a)\frac{2}{3}x-\frac{1}{2}=\frac{5}{12}\)
\(\Rightarrow\frac{2}{3}x=\frac{5}{12}+\frac{1}{2}=\frac{11}{12}\)
\(\Rightarrow x=\frac{11}{12}:\frac{2}{3}=\frac{11}{8}\)
\(b)\left(2\frac{4}{5}x-50\right):\frac{2}{3}=51\)
\(\Rightarrow\frac{14}{5}x-50=51.\frac{2}{3}=34\)
\(\Rightarrow\frac{14}{5}x=34+50=84\)
\(\Rightarrow x=84:\frac{14}{5}=30\)
a) 2/3.x - 1/2 = 5/12
2/3.x = 5/12 + 1/2
2/3.x = 11/12
x = 11/12 : 2/3
x = 11/8
b) \(\left(2\frac{4}{5}.x-50\right):\frac{2}{3}=51\)
\(\frac{14}{5}.x-50=51.\frac{2}{3}\)
\(\frac{14}{5}.x-50=34\)
\(\frac{14}{5}.x=34+50\)
\(\frac{14}{5}.x=84\)
\(x=84:\frac{14}{5}\)
\(x=30\)
Bài 1:
\(\frac{7}{12}+\frac{-8}{15}=\frac{7}{12}-\frac{8}{15}=\frac{35}{60}-\frac{32}{60}=\frac{3}{60}=\frac{1}{20}\)
\(\frac{5}{12}+\frac{-8}{15}=\frac{5}{12}-\frac{8}{15}=\frac{25}{60}-\frac{32}{60}=\frac{-7}{60}\)
Bài 2:
\(a,x-23=-56\)
\(x=-56+23\)
\(x=-33\)
\(b,2x-36=24\)
\(2x=60\)
\(x=30\)
\(c,x-\frac{4}{5}=\frac{3}{2}\)
\(x=\frac{3}{2}+\frac{4}{5}=\frac{23}{10}\)
\(d,x-46=123\)
\(x=123+46=169\)
\(e,2x-25=-45\)
\(2x=-20\)
\(x=-10\)
\(f,x-\frac{2}{3}=-\frac{7}{5}\)
\(x=-\frac{7}{5}+\frac{2}{3}=-\frac{11}{15}\)
=.= hk tốt!!
* \(\left(x-\frac{5}{24}\right)\cdot\frac{18}{7}=-\frac{12}{7}\)
<=> \(x-\frac{5}{24}=-\frac{2}{3}\)
<=> \(x=-\frac{11}{24}\)
* \(\frac{3}{4}+\frac{1}{4}\left(x-1\right)=\frac{1}{2}\)
<=> \(\frac{x-1}{4}=\frac{-1}{4}\)
<=> \(x-1=-1\)
<=> \(x=0\)
* \(\left(4x-\frac{1}{2}\right)\left(\frac{x}{3}-\frac{1}{5}\right)=0\)
<=> \(\orbr{\begin{cases}4x-\frac{1}{2}=0\\\frac{x}{3}-\frac{1}{5}=0\end{cases}}\)<=> \(\orbr{\begin{cases}4x=\frac{1}{2}\\\frac{x}{3}=\frac{1}{5}\end{cases}}\)<=> \(\orbr{\begin{cases}x=\frac{1}{8}\\x=\frac{3}{5}\end{cases}}\)
các bạn ơi mình đang cần gấp . Mình chỉ còn 20 phút thui . HUHU
Bài làm :
1) \(\frac{x+11}{4}=\frac{2x+4}{5}\)
\(\Leftrightarrow\left(x+11\right).5=4.\left(2x+4\right)\)
\(\Leftrightarrow5x+55=8x+16\)
\(\Leftrightarrow5x-8x=16-55\)
\(\Leftrightarrow-3x=-39\)
\(\Leftrightarrow x=\frac{-39}{-3}=\frac{39}{3}=13\)
2)\(\frac{x+4}{x+10}=\frac{3}{5}\)
\(\Leftrightarrow\left(x+4\right).5=\left(x+10\right).3\)
\(\Leftrightarrow5x+20=3x+30\)
\(\Leftrightarrow5x-3x=30-20\)
\(\Leftrightarrow2x=10\)
\(\Leftrightarrow x=\frac{10}{2}=5\)
3)\(\frac{x+8}{x+14}=\frac{2}{3}\)
\(\Leftrightarrow\left(x+8\right).3=\left(x+14\right).2\)
\(\Leftrightarrow3x+24=2x+28\)
\(\Leftrightarrow3x-2x=28-24\)
\(\Leftrightarrow x=4\)
1) Tìm x
\(\frac{11}{2}.x+\frac{1}{3}.x=1\)
\(\Rightarrow x\left(\frac{11}{2}+\frac{1}{3}\right)=1\)
\(\Rightarrow x\left(\frac{33}{6}+\frac{2}{6}\right)=1\)
\(\Rightarrow x.\frac{35}{6}=1\)
\(\Rightarrow x=\frac{6}{35}\)
2) So sánh
\(\frac{59}{40}< \frac{50}{31}\)( cái này bạn quy đồng là ra, mik chỉ ghi kq, bạn tự tính )
3)\(\frac{1}{3}+\frac{4}{7}-\frac{5}{14}-\frac{1}{2}-\frac{2}{3}\)
\(=\left(\frac{1}{3}-\frac{2}{3}\right)+\left(\frac{4}{7}-\frac{5}{14}\right)-\frac{1}{2}\)
\(=-\frac{1}{3}+\frac{3}{14}-\frac{1}{2}\)
\(=-\frac{13}{21}\)
1)\(\frac{11}{2}.x+\frac{1}{3}.x=1\)
\(x.\left(\frac{11}{2}+\frac{1}{3}=1\right)\)
\(x.\frac{35}{6}=1\)
\(x=1:\frac{35}{6}\)
\(x=\frac{6}{35}\)
2) Ta có:
\(\frac{59}{40}=\frac{1829}{1240}\)
\(\frac{50}{31}=\frac{2000}{1240}\)
Vì \(2000>1829\Rightarrow\frac{2000}{1240}>\frac{1829}{1240}\Rightarrow\frac{50}{31}>\frac{59}{40}\)
3)\(\frac{1}{3}+\frac{4}{7}-\frac{5}{14}-\frac{1}{2}-\frac{2}{3}\)
\(=\left(\frac{1}{3}-\frac{2}{3}\right)+\left(\frac{4}{7}-\frac{5}{14}-\frac{1}{2}\right)\)
\(=-\frac{1}{3}+\left(\frac{8}{14}-\frac{5}{14}-\frac{7}{14}\right)\)
\(=\frac{-1}{3}+\frac{-4}{14}\)
\(=\frac{-1}{3}+\frac{-2}{7}\)
\(=\frac{-7}{21}+\frac{-6}{21}\)
\(=\frac{-13}{21}\)
Bài 2 :
1) \(x-70=-45\) 2) \(\frac{4}{7}:x=\frac{12}{28}\)
\(\Rightarrow\) \(x=-45+70\) \(\Rightarrow x=\frac{4}{7}:\frac{12}{28}\)
\(\Rightarrow\) \(x=25\) \(\Rightarrow x=\frac{4}{3}\)
Vậy \(x=25\) Vậy \(x=\frac{4}{3}\)
3) Giống câu c) ở bài 1
4) \(x-50=-35\) 5) \(\frac{4}{7}.x=\frac{11}{18}\)
\(\Rightarrow x=-35+50\) \(\Rightarrow x=\frac{11}{28}:\frac{4}{7}\)
\(\Rightarrow x=15\) \(\Rightarrow x=\frac{77}{72}\)
Vậy \(x=15\) Vậy \(x=\frac{77}{72}\)
6) \(\left(\frac{2}{3}x+2,5\right):2\frac{2}{6}=6\)
\(\Rightarrow\)\(\left(\frac{2}{3}x+2,5\right):\frac{14}{6}=6\)
\(\Rightarrow\) \(\frac{2}{3}x+2,5=6.\frac{14}{6}\)
\(\Rightarrow\frac{2}{3}x+2,5=14\)
\(\Rightarrow\frac{2}{3}x=\frac{23}{2}\)
\(\Rightarrow x=\frac{23}{2}:\frac{2}{3}\)
\(\Rightarrow x=\frac{69}{4}\)
Vậy \(x=\frac{69}{4}\)
Bài 1:
1) \(\frac{7}{5}+\frac{-8}{5}=-\frac{1}{5}\)
2) \(-\frac{6}{5}.\frac{15}{24}=-\frac{3}{4}\)
3) \(\left(\frac{2}{3}+1,5\right)-3,5:7\frac{1}{2}=\)\(\frac{13}{6}-\frac{7}{15}=\frac{17}{10}\)
4) \(\frac{5}{8}-\frac{-7}{9}=\frac{5}{8}+\frac{7}{9}=\frac{101}{72}\)
5)\(\frac{-7}{3}.\frac{12}{28}=-1\)
\(\frac{2}{3}.x-\frac{1}{2}.x=\frac{5}{12}+x\)
\(\Rightarrow\frac{2}{3}.x-\frac{1}{2}.x-x=\frac{5}{12}\)
\(x.\left(\frac{2}{3}-\frac{1}{2}-1\right)=\frac{5}{12}\)
\(x.\left(\frac{-5}{6}\right)=\frac{5}{12}\)
\(x=\frac{5}{12}:\left(\frac{-5}{6}\right)\)
\(x=\frac{-1}{2}\)