67,6:\(\dfrac{\dfrac{2}{5}\times x+3}{20+9.5}=\dfrac{132}{5}\)
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H9
HT.Phong (9A5)
CTVHS
24 tháng 8 2023
a) \(\dfrac{2}{5}\times?=\dfrac{3}{10}\)
\(?=\dfrac{3}{10}:\dfrac{2}{5}=\dfrac{3}{4}\)
b) \(\dfrac{1}{8}:?=\dfrac{1}{5}\)
\(?=\dfrac{1}{8}:\dfrac{1}{5}=\dfrac{5}{8}\)
24 tháng 8 2023
a: Phân số cần tìm là: \(\dfrac{3}{10}:\dfrac{2}{5}=\dfrac{3}{10}\cdot\dfrac{5}{2}=\dfrac{15}{20}=\dfrac{3}{4}\)
b: Phân số cần tìm là \(\dfrac{1}{8}:\dfrac{1}{5}=\dfrac{5}{8}\)
H9
HT.Phong (9A5)
CTVHS
24 tháng 8 2023
a) \(\dfrac{2}{3}\times\dfrac{4}{5}=\dfrac{4}{5}\times\dfrac{2}{3}\)
b) \(\left(\dfrac{1}{3}\times\dfrac{2}{5}\right)\times\dfrac{3}{4}=\dfrac{1}{3}\times\left(\dfrac{2}{5}\times\dfrac{3}{4}\right)\)
c) \(\left(\dfrac{1}{3}-\dfrac{2}{15}\right)\times\dfrac{3}{4}=\dfrac{1}{3}\times\dfrac{3}{4}+\dfrac{2}{15}\times\dfrac{3}{4}\)
31 tháng 7 2022
1: \(A=\dfrac{-25}{27}-\dfrac{31}{42}+\dfrac{7}{27}+\dfrac{3}{42}=\dfrac{-2}{3}-\dfrac{2}{3}=\dfrac{-4}{3}\)
2: \(B=\dfrac{10.3-\left(9.5-4.5\right)\cdot2}{1.2-1.5}=\dfrac{10.3-10}{-0.3}=-1\)
c: \(=\dfrac{3}{49}\left(\dfrac{19}{2}-\dfrac{5}{2}\right)-\left(\dfrac{1}{20}-\dfrac{5}{20}\right)^2\cdot\left(\dfrac{-7}{14}-\dfrac{193}{14}\right)\)
\(=\dfrac{3}{49}\cdot7-\dfrac{1}{25}\cdot\dfrac{-200}{14}\)
\(=\dfrac{3}{7}+\dfrac{8}{14}=1\)
31 tháng 12 2022
a: =>x*2/15=2/7
=>x=2/7:2/15=2/7*15/2=15/7
b: x=3:7/5=15/7
c: x=-1/2:4/9=-1/2*9/4=-9/8
d: x=-8/3:3/8=-64/9
g: =>4/11x=2/5+1/3=6/15+5/15=11/15
=>x=11/15:4/11=121/60
l: =>1/4:x=1-3/2=-1/2
=>x=-1/4:1/2=-1/4*2=-1/2
k: =>x:7=-1/3+5/2=-2/6+15/6=13/6
=>x=91/6
O
5 tháng 5 2022
a) \(\dfrac{2}{3}\times\dfrac{1}{4}-\dfrac{1}{3}\times\dfrac{1}{2}=\dfrac{2}{12}-\dfrac{1}{6}=\dfrac{1}{6}-\dfrac{1}{6}=\dfrac{0}{6}=0\)
b) \(\dfrac{8}{5}\times\dfrac{1}{4}-\dfrac{2}{5}\times\dfrac{1}{2}-\dfrac{1}{2}\times\dfrac{1}{5}=\dfrac{8}{20}-\dfrac{2}{10}-\dfrac{1}{10}=\dfrac{4}{10}-\dfrac{2}{10}-\dfrac{1}{10}=\dfrac{4-2-1}{10}=\dfrac{1}{10}\)
DL
4
9 tháng 5 2023
\(\dfrac{11}{5}-x=\dfrac{3}{5}:\dfrac{5}{3}\)
\(\dfrac{11}{5}-x=\dfrac{9}{25}\)
\(x=\dfrac{11}{5}-\dfrac{9}{25}=\dfrac{46}{25}\)
NT
Nguyễn Thị Thương Hoài
Giáo viên
VIP
9 tháng 5 2023
\(\dfrac{5}{3}\) \(\times\)[ 2\(\dfrac{1}{5}\) - \(x\)]\(^2\) = \(\dfrac{3}{5}\)
[\(\dfrac{11}{5}\) - \(x\)]2 = \(\dfrac{3}{5}\) : \(\dfrac{5}{3}\)
[ \(\dfrac{11}{5}\) - \(x\)]2 = \(\dfrac{3}{5}\) \(\times\) \(\dfrac{3}{5}\)
[ \(\dfrac{11}{5}\) - \(x\)]2 = \(\dfrac{9}{25}\)
\(\left[{}\begin{matrix}\dfrac{11}{5}-x=-\dfrac{3}{5}\\\dfrac{11}{5}-x=\dfrac{3}{5}\end{matrix}\right.\)
\(\left[{}\begin{matrix}x=\dfrac{11}{5}+\dfrac{3}{5}\\x=\dfrac{11}{5}-\dfrac{3}{5}\end{matrix}\right.\)
\(\left[{}\begin{matrix}x=\dfrac{14}{5}\\x=\dfrac{8}{5}\end{matrix}\right.\)
\(x\in\) { \(\dfrac{8}{5};\dfrac{14}{5}\)}
4 tháng 12 2021
a: \(\Leftrightarrow\left(x-1\right)^2=81\)
\(\Leftrightarrow\left[{}\begin{matrix}x-1=9\\x-1=-9\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=10\\x=-8\end{matrix}\right.\)
HQ
Hà Quang Minh
Giáo viên
27 tháng 11 2023
a) $\frac{2}{5} \times \frac{3}{8} \times \frac{3}{4} = \frac{{2 \times 3 \times 3}}{{5 \times 8 \times 4}} = \frac{{18}}{{160}} = \frac{9}{{80}}$
b) $\frac{1}{3} \times \frac{1}{6} \times \frac{1}{9} = \frac{{1 \times 1 \times 1}}{{3 \times 6 \times 9}} = \frac{1}{{162}}$
c) $\frac{3}{4}:\frac{1}{5}:\frac{7}{8} = \frac{3}{4} \times \frac{5}{1} \times \frac{8}{7} = \frac{{3 \times 5 \times 8}}{{4 \times 1 \times 7}} = \frac{{120}}{{28}} = \frac{{30}}{7}$
d) $\frac{3}{5}:\frac{1}{5}:\frac{3}{8} = \frac{3}{5} \times \frac{5}{1} \times \frac{8}{3} = \frac{{3 \times 5 \times 8}}{{5 \times 1 \times 3}} = 8$
18 tháng 9 2021
1) \(\dfrac{11}{12}-\left(\dfrac{2}{5}+x\right)=\dfrac{2}{3}\)
\(\Leftrightarrow\dfrac{11}{12}-\dfrac{2}{5}-x=\dfrac{2}{3}\)
\(\Leftrightarrow x=\dfrac{11}{12}-\dfrac{2}{5}-\dfrac{2}{3}\)
\(\Leftrightarrow x=-\dfrac{3}{20}\)
2) \(2x\left(x-\dfrac{1}{7}\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}2x=0\\x-\dfrac{1}{7}=0\end{matrix}\right.\)\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=\dfrac{1}{7}\end{matrix}\right.\)
3) \(\dfrac{3}{4}+\dfrac{1}{4}:x=\dfrac{2}{5}\)
\(\Leftrightarrow\dfrac{1}{4x}=\dfrac{2}{5}-\dfrac{3}{4}\)
\(\Leftrightarrow\dfrac{1}{4x}=-\dfrac{7}{20}\)
\(\Leftrightarrow4x=-\dfrac{20}{7}\)
\(\Leftrightarrow x=-\dfrac{5}{7}\)
\(67,6:\dfrac{\dfrac{2}{5}x+3}{20+9.5}=\dfrac{132}{5}\)
\(\Rightarrow\dfrac{\dfrac{2}{5}x+3}{45}=67,6:\dfrac{132}{5}\)
\(\Rightarrow\dfrac{\dfrac{2}{5}x+3}{65}=\dfrac{169}{66}\)
\(\Rightarrow\left(\dfrac{2}{5}x+3\right).66=132.65\)
\(\Rightarrow\dfrac{2}{5}x+3=\dfrac{10985}{66}\)
\(\Rightarrow\dfrac{2}{5}x=\dfrac{10985}{66}-3=\dfrac{10787}{66}\)
\(\Rightarrow x=\dfrac{10787}{66}:\dfrac{2}{5}=\dfrac{53935}{132}\)
Vậy.........................
sửa chút nha:
+) dòng thứ 2: \(\dfrac{\dfrac{2}{5}x+3}{20+45}=...\)
+) dòng thứ 4: \(.....=169.65\)