a) Lm r nkoa!

b) \(\left(0,25x\right):3=\frac{5}{6}:0,125\)

\(=\left(0,25x\right):3=\frac{20}{3}\)

\(\Rightarrow0,25x=\frac{20}{3}\cdot3=20\)

\(\Rightarrow x=20:0,25=80\)

\(\Rightarrow x=80\)

c) \(0,01:2,5=\left(0,75x\right):0,75\)

\(=\frac{1}{250}=\left(0,75x\right):0,75\)

\(\Rightarrow0,75x=\frac{1}{250}\cdot0,75=\frac{3}{1000}\)

\(\Rightarrow x=\frac{3}{1000}:0,75=\frac{1}{250}\)

\(\Rightarrow x=\frac{1}{250}\)

d) \(1\frac{1}{3}:0,8=\frac{2}{3}:\left(0,1x\right)\)

\(=\frac{5}{3}=\frac{2}{3}:\left(0,1x\right)\)

\(\Rightarrow0,1x=\frac{2}{3}:\frac{5}{3}=\frac{2}{5}\)

\(\Rightarrow x=\frac{2}{5}:0,1=4\)

\(\Rightarrow4\)

\(a,3,8:2x=\frac{1}{4}:2\frac{2}{3}\)

\(\Leftrightarrow3,8:2x=\frac{3}{32}\)

\(\Leftrightarrow2x=3,8:\frac{3}{32}\)

\(\Leftrightarrow2x=\frac{608}{15}\)

\(\Leftrightarrow x=\frac{304}{15}\)

\(b,0,25x:3=\frac{5}{6}:0,125\)

\(\Leftrightarrow0,25x:3=\frac{20}{3}\)

\(\Leftrightarrow0,25x=20\)

\(\Leftrightarrow x=80\)

\(c,0,01:2,5=0,75x:0,75\)

\(\Leftrightarrow0,75x:0,75=\frac{1}{250}\)

\(\Leftrightarrow x=\frac{1}{250}\)

Mik lm hơi tắt chỗ nào chw hiểu thì hỏi mik nhé

làm 1 bài mẫu nha

a) \(\left(\frac{1}{3}.x\right):\frac{2}{3}=\frac{25}{6}\)

\(\Rightarrow\frac{1}{3}x=\frac{25}{9}\)

\(\Rightarrow x=\frac{25}{9}:\frac{1}{3}\)

\(\Rightarrow x=\frac{25}{3}\)

các bài sau dễ lắm

a) \(\left(\frac{1}{3}x\right):\frac{2}{3}=1\frac{2}{3}:\frac{2}{5}\)

\(\Rightarrow\frac{1}{3}x:\frac{2}{3}=\frac{25}{6}\)

\(\Rightarrow\frac{1}{3}x=\frac{5}{3}\)

\(\Rightarrow x=\frac{5}{3}:\frac{1}{3}\)

\(\Rightarrow x=5\)

a) \(\left(\frac{1}{3}\cdot x\right):\frac{2}{3}=1\frac{2}{3}:\frac{2}{5}\)

\(\left(\frac{1}{3}\cdot x\right):\frac{2}{3}=\frac{25}{6}\)

\(\frac{1}{3}x=\frac{25}{6}\cdot\frac{2}{3}\)

\(\frac{1}{3}x=\frac{25}{9}\)

\(x=\frac{25}{9}:\frac{1}{3}\)

\(x=\frac{25}{3}\)

b) \(4,5:0,3=2,25:\left(0,1x\right)\)

\(15=2,25:\left(0,1x\right)\)

\(2,25:15=0,1x\)

\(0,15=0,1x\)

\(0,15:0,1=x\)

\(1,5=x\)

c) \(8:\left(\frac{1}{4}\cdot x\right)=2:0,02\)

\(8:\left(\frac{1}{4}\cdot x\right)=100\)

\(\frac{1}{4}\cdot x=8:100\)

\(\frac{1}{4}\cdot x=0,08\)

\(x=0,08:\frac{1}{4}\)

\(x=0,32\)

d) \(3:2\frac{1}{4}=\frac{3}{4}:\left(6\cdot x\right)\)

\(\frac{4}{3}=\frac{3}{4}:\left(6\cdot x\right)\)

\(\frac{3}{4}:\frac{4}{3}=6\cdot x\)

\(\frac{9}{16}=6\cdot x\)

\(\frac{9}{16}:6=x\)

\(\frac{3}{32}=x\)

e) \(3,8:\left(2\cdot x\right)=\frac{1}{4}:2\frac{2}{3}\)

\(3,8:\left(2\cdot x\right)=\frac{3}{32}\)

\(2\cdot x=3,8:\frac{3}{32}\)

\(2\cdot x=\frac{608}{15}\)

\(x=\frac{608}{15}:2\)

\(x=\frac{304}{15}\)

f) \(\left(0,25\cdot x\right):3=\frac{5}{6}:0,125\)

\(\left(0,25\cdot x\right):3=\frac{20}{3}\)

\(0,25\cdot x=\frac{20}{3}\cdot3\)

\(0,25\cdot x=20\)

\(x=20:0,25\)

\(x=80\)

g) \(1\frac{1}{3}:0,8=\frac{2}{3}:\left(0,1\cdot x\right)\)

\(\frac{5}{3}=\frac{2}{3}:\left(0,1\cdot x\right)\)

\(\frac{2}{3}:\frac{5}{3}=0,1\cdot x\)

\(\frac{2}{5}=0,1x\)

\(\frac{2}{5}:0,1=x\)

\(4=x\)

(Nhớ thử lại kết quả nhé)

\(a,-0,52:x=-9,36:16,38\)

\(\Leftrightarrow\frac{-13}{25}:x=\frac{-4}{7}\)

\(\Leftrightarrow x=\frac{-13}{25}:\frac{-4}{7}\)

\(\Leftrightarrow x=\frac{91}{100}\)

\(b,\frac{x}{-15}=\frac{-60}{x}\)

\(\Leftrightarrow x^2=900\)

\(\Leftrightarrow x^2=\left(30,-30\right)^2\)

\(\Leftrightarrow\orbr{\begin{cases}x=30\\x=-30\end{cases}}\)

\(c,\frac{-2}{x}=\frac{-x}{8}\)

\(\Leftrightarrow-\left(x^2\right)=-16\)

\(\Leftrightarrow x^2=16\)

\(\Leftrightarrow x^2=\left(4,-4\right)^2\)

\(\Leftrightarrow\orbr{\begin{cases}x=-4\\x=4\end{cases}}\)

\(d.3,8\div2x=\frac{1}{4}:2\frac{2}{3}\)

\(\Leftrightarrow3,8\div2x=\frac{3}{32}\)

\(\Leftrightarrow2x=3,8\div\frac{3}{32}\)

\(\Leftrightarrow2x=\frac{608}{15}\)

\(\Leftrightarrow x=\frac{608}{15}\div2\)

\(\Leftrightarrow x=\frac{304}{15}\)

\(e.0,25x\div3=\frac{5}{6}:0,125\)

\(\Leftrightarrow0,25x\div3=\frac{20}{3}\)

\(\Leftrightarrow0,25x=\frac{20}{3}.3\)

\(\Leftrightarrow\frac{1}{4}x=20\)

\(\Leftrightarrow x=20:\frac{1}{4}\)

\(\Leftrightarrow x=80\)

1) a) Ta có: \(\frac{x}{-15}=\frac{-60}{x}\) \(\Rightarrow x^2=\left(-15\right).\left(-60\right)=900\)

                                               \(\Rightarrow x=30\)

b) \(\frac{-2}{x}=\frac{-x}{\frac{8}{25}}\) \(\Rightarrow x.\left(-x\right)=\left(-2\right).\frac{8}{25}\)

                               \(\Rightarrow x.\left(-x\right)=\frac{-16}{25}\)

                                \(\Rightarrow x.\left(-x\right)=\left(\frac{-4}{5}\right).\frac{4}{5}\)

Vậy \(x=\frac{4}{5}\)

2) a) \(3,8: \left(2x\right)=\frac{1}{4}:2\frac{2}{3}\)

\(\Rightarrow3,8: \left(2x\right)=\frac{3}{32}\)

\(\Rightarrow2x=\frac{3}{32}:3,8=\frac{15}{608}\)

\(x=\frac{15}{608}:2=\frac{15}{1216}\)

Vậy \(x=\frac{15}{1216}\)

b) \(\left(0,25x\right):3=\frac{5}{6}:0,125\)

\(\Rightarrow\left(0,25x\right):3=\frac{20}{3}\)

\(\Rightarrow0,25x=\frac{20}{3}.3=20\)

\(\Rightarrow x=20:0,25=80\)

Vậy x = 80

c) \(0,01:2,5=\left(0,75x\right):0,75\)

\(\Rightarrow\frac{1}{250}=\left(0,75x\right):0,75\)

\(\Leftrightarrow0,75x=\frac{1}{250}.0,75=\frac{3}{1000}\)

\(\Rightarrow x=\frac{3}{1000}:0,75=\frac{1}{250}\)

Vậy \(x=\frac{1}{250}\)

d) \(1\frac{1}{3}:0,8=\frac{2}{3}:\left(0,1x\right)\)

\(\Rightarrow\frac{5}{3}=\frac{2}{3}:\left(0,1x\right)\)

\(\Rightarrow0,1x=\frac{5}{3}.\frac{2}{3}=\frac{10}{9}\)

\(\Rightarrow x=\frac{10}{9}:0,1=\frac{100}{9}\)

Vậy \(x=\frac{100}{9}\)

a) \(\frac{x}{-15}=\frac{-60}{x}\Leftrightarrow x.x=-15.\left(-60\right)\Leftrightarrow x^2=900\Leftrightarrow x^2=\orbr{\begin{cases}30^2\\\left(-30\right)^2\end{cases}}\Leftrightarrow x=\orbr{\begin{cases}30\\-30\end{cases}}\)

3)  \(\frac{x}{4}=\frac{y}{7}\Leftrightarrow\frac{x^2}{4}=\frac{xy}{7}\Leftrightarrow\frac{x^2}{4}=\frac{112}{7}\Leftrightarrow x^2=\frac{448}{7}=64\Leftrightarrow x=\orbr{\begin{cases}8\\-8\end{cases}}\)                                                             \(\Rightarrow y=\orbr{\begin{cases}112:8=14\\112:\left(-8\right)=-14\end{cases}}\)

Tìm x trong các tỉ lệ thức sau :

\(\left(a\right)3,8\div\left(2x\right)=\frac{1}{4}\div2\frac{2}{3}\)

\(3,8\div\left(2x\right)=\frac{3}{32}\)

\(2x=3,8\div\frac{3}{32}\)

\(2x=40\frac{8}{15}\)

\(x=20\frac{4}{15}\)

\(\left(0,25x\right)\div3=\frac{5}{6}\div0,125\)

\(\left(0,25x\right)\div3=6\frac{2}{3}\)

\(\left(0,25x\right)=6\frac{2}{5}\times3\)

\(\left(0,25x\right)=20\)

\(x=80\)

\(0,01\div2,5=\left(0,75x\right)\div0,75\)

\(0,004=\left(0,75x\right)\div0,75\)

\(0,75x=0,75\times0,004\)

\(0,75x=0,003\)

\(x=0,004\)

\(1\frac{1}{3}\div0,8=\frac{2}{3}\div\left(0,1x\right)\)

\(1\frac{2}{3}=\frac{2}{3}\div\left(0,1x\right)\)

\(\left(0,1x\right)=\frac{2}{3}\div1\frac{2}{3}\)

\(\left(0,1x\right)=\frac{2}{5}\)

\(x=4\)

Dung ko z

bạn ghi ra đi mk giải cho (kb để mk ns cho dễ hiểu)