5/9 x 8/17 + 4/9 x 8/17
K
Khách
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8/7: x =4/5
17 tháng 2 2022
Câu 1: Tìm x:
a) 2/5× x =(thiếu đề)
8/7: x =4/5
x=8/7:4/5
x=10/7
Câu 2: Tính bằng cách thuận tiện nhất
5/9× 8/17 + 4/9 × 8/17
=(5/9+4/9)x8/17
=1x8/17=8/17
AE
2
V
25 tháng 4 2019
bài 1
\(\frac{2}{5}+x=4\) , \(\frac{8}{7}:x=\frac{4}{5}\)
\(\Rightarrow\)\(x=4-\frac{2}{5}\) , \(\Rightarrow\)\(x=\frac{8}{7}:\frac{4}{5}\)
\(\Rightarrow\)\(x=\frac{18}{5}\) , \(\Rightarrow\) \(x=\frac{10}{7}\)
25 tháng 4 2019
tính cách thuận tiện là dấu = là x vì viết nhầm
2 tháng 7 2021
1) Ta có: \(\left(\dfrac{3}{4}\cdot\dfrac{5}{97}+\dfrac{1}{9}\cdot\dfrac{13}{47}\right)\cdot\left(\dfrac{1}{5}-\dfrac{7}{25}\cdot\dfrac{5}{7}\right)\)
\(=\left(\dfrac{3}{4}\cdot\dfrac{5}{97}+\dfrac{1}{9}\cdot\dfrac{13}{47}\right)\cdot\left(\dfrac{1}{5}-\dfrac{1}{5}\right)\)
=0
2) Ta có: \(\dfrac{8}{17}\cdot\dfrac{4}{15}+\dfrac{8}{17}\cdot\dfrac{22}{15}-\dfrac{8}{15}\cdot\dfrac{9}{17}\)
\(=\dfrac{8}{17}\left(\dfrac{4}{15}+\dfrac{22}{15}-\dfrac{9}{15}\right)\)
\(=\dfrac{8}{17}\cdot\dfrac{15}{15}=\dfrac{8}{17}\)
3) Ta có: \(\dfrac{2021}{2}\cdot\dfrac{1}{3}+\dfrac{4042}{4}\cdot\dfrac{1}{5}+\dfrac{6063}{3}\cdot\dfrac{22}{15}\)
\(=\dfrac{2021}{2}\left(\dfrac{1}{3}+\dfrac{1}{5}\right)+2021\cdot\dfrac{22}{15}\)
\(=\dfrac{2021}{2}\cdot\dfrac{8}{15}+\dfrac{2021}{2}\cdot\dfrac{44}{15}\)
\(=\dfrac{2021}{2}\cdot\dfrac{52}{15}\)
\(=\dfrac{52546}{15}\)
4) Ta có: \(\dfrac{4}{7}\cdot\dfrac{2}{13}+\dfrac{8}{13}:\dfrac{7}{4}+\dfrac{4}{7}:\dfrac{13}{2}+\dfrac{4}{7}\cdot\dfrac{1}{13}\)
\(=\dfrac{4}{7}\left(\dfrac{2}{13}+\dfrac{8}{13}+\dfrac{2}{13}+\dfrac{1}{13}\right)\)
\(=\dfrac{4}{7}\)
5 tháng 2 2022
Bài 1:
\(\Leftrightarrow2^n\cdot\dfrac{9}{2}=9\cdot5^n\)
\(\Leftrightarrow2^n=2\cdot5^n\)
\(\Leftrightarrow2^{n-1}=5^n\)
Bài 2:
a: \(A=\dfrac{2^8+3^8}{2^8}=1+\dfrac{3^8}{2^8}\)
b: \(B=\left(2^{17}+17^2\right)\cdot\left(9^{15}-15^9\right)\cdot\left(16-16\right)=0\)
26 tháng 7 2023
a: \(=\dfrac{3}{5}:\dfrac{7}{5}=\dfrac{3}{5}\cdot\dfrac{5}{7}=\dfrac{3}{7}\)
b: \(=\dfrac{9}{17}\left(\dfrac{8}{5}-\dfrac{3}{5}\right)+\dfrac{8}{17}\)
=9/17+8/17=1
c: =>x-3/10=7/15*1/5=7/75
=>x=7/75+3/10=59/150
DC
3
11 tháng 4 2019
\(a,0,5x-\frac{2}{3}x=\frac{7}{12}\Rightarrow\frac{1}{2}x-\frac{2}{3}x=\frac{7}{12}\)
\(\Rightarrow x\left(\frac{1}{2}-\frac{2}{3}\right)=\frac{7}{12}\Rightarrow x\cdot\left(\frac{3}{6}-\frac{4}{6}\right)=\frac{7}{12}\)
\(\Rightarrow x\cdot\left(-1\right)=\frac{7}{12}\Rightarrow x=\frac{7}{12}:\left(-1\right)=\frac{7}{-12}\)
\(c,\frac{\left(x-5\right)}{12}\cdot\frac{9}{29}=\frac{-6}{29}\Rightarrow\frac{\left(x-5\right)}{12}=\frac{-6}{29}:\frac{9}{26}\)
\(\frac{\Rightarrow\left(x-5\right)}{12}=\frac{-6}{9}=\frac{-2}{3}\Rightarrow x-5=-\frac{2}{3}\cdot12\)
\(\Rightarrow x-5=\frac{-24}{3}=-8\Rightarrow x=-8+5=-3\)
BA
11 tháng 4 2019
\(a,0,5x-\frac{2}{3}x=\frac{7}{12}\)
\(\Rightarrow\frac{1}{2}x-\frac{2}{3}x=\frac{7}{12}\)
\(\Rightarrow-\frac{1}{6}x=\frac{7}{12}\)
\(\Rightarrow x=-\frac{7}{2}\)
\(c,\frac{x-5}{12}\cdot\frac{9}{29}=-\frac{6}{29}\)
\(\Rightarrow\frac{x-5}{12}=-\frac{2}{3}\)
\(\Rightarrow x-5=12.\left(-\frac{2}{3}\right)\)
\(\Rightarrow x-5=-8\)
\(\Rightarrow x=-3\)
Bài làm
\(\frac{5}{9}x\frac{8}{17}+\frac{4}{9}x\frac{8}{17}\)
\(=\frac{8}{17}x\left(\frac{5}{9}+\frac{4}{9}\right)\)
\(=\frac{8}{17}x\frac{9}{9}\)
\(=\frac{8}{17}x1\)
\(=\frac{18}{7}\)
# Chúc bạn học tốt #
\(\frac{5}{9}.\frac{8}{17}+\frac{4}{9}.\frac{8}{17}\)
\(=\frac{8}{17}\left(\frac{5}{9}+\frac{4}{9}\right)\)
\(=\frac{8}{17}.1=\frac{8}{17}\)