\(\dfrac{-28}{35}=\dfrac{16}{x}\)
giúp mình với mình cần gấp
\(\dfrac{-28}{35}\)=\(\dfrac{16}{x}\)
\(\dfrac{x+7}{15}\)=\(\dfrac{-24}{36}\)
giúp mình
a: \(\Leftrightarrow\dfrac{16}{x}=\dfrac{-4}{5}\)
hay x=-20
b: =>x+7=-10
hay x=-17
\(-\dfrac{28}{35}=\dfrac{16}{x}\Leftrightarrow-\dfrac{4}{5}=\dfrac{16}{x}\)
\(\Rightarrow-4x=5\cdot16\)
\(\Rightarrow-4x=80\)
\(\Rightarrow x=-20\)
\(\dfrac{x+7}{15}=-\dfrac{24}{36}\Leftrightarrow\)\(\dfrac{x+7}{15}=-\dfrac{2}{3}\)
\(\Rightarrow3\left(x+7\right)=-2\cdot15\)
\(x+7=-30\div3\)
x+7=-10
x=-10-7
x=-17
Tìm x biết:
\(\dfrac{-6}{x}\)=\(\dfrac{32}{-35}\)
Giải giúp mình với ạ,mình đang cần gấp á =v=
=>6/x=32/35
=>x=6:32/35=6*35/32=210/32=105/16
Tính Nhanh:
B=\(\dfrac{1}{2}\)+\(\dfrac{1}{4}\)+\(\dfrac{1}{8}\)+\(\dfrac{1}{16}\)+\(\dfrac{1}{32}\)+\(\dfrac{1}{64}\)
Giúp mình với mình cần gấp ạ
\(B=\dfrac{1}{2}+\dfrac{1}{4}+\dfrac{1}{8}+\dfrac{1}{16}+\dfrac{1}{32}+\dfrac{1}{64}\)
=>\(B=\dfrac{32}{64}+\dfrac{16}{64}+\dfrac{6}{64}+\dfrac{2}{64}+\dfrac{1}{64}\)
=>\(B=\dfrac{32+16+6+2+1}{64}\)
=>\(B=\dfrac{63}{64}\)
\(B=\dfrac{1}{2}+\dfrac{1}{2^2}+\dfrac{1}{2^3}+...+\dfrac{1}{2^6}\)
\(2B=1+\dfrac{1}{2}+...+\dfrac{1}{2^5}\)
\(\Rightarrow2B-B=1-\dfrac{1}{2^6}\)
\(\Rightarrow B=1-\dfrac{1}{2^6}=1-\dfrac{1}{64}=\dfrac{63}{64}\)
\(\dfrac{-1}{15}-\dfrac{1}{16}\)
Giúp mình với cần gấp chiều nay thi gòi
\(|\)2,5 - x\(|\) = 1,3
1,6 - \(|\)x - 0,2\(|\) = 0
13x = 169
\(\dfrac{-2\dfrac{ }{ }}{x}\) = \(\dfrac{-x}{\dfrac{8}{25}}\)
GIÚP MÌNH VỚI MÌNH ĐANG CẦN GẤP
a) Ta có: \(\left|2.5-x\right|=1.3\)
\(\Leftrightarrow\left|x-2.5\right|=1.3\)
\(\Leftrightarrow\left[{}\begin{matrix}x-2.5=1.3\\x-2.5=-1.3\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=3.8\\x=-1.3+2.5=1.2\end{matrix}\right.\)
Vậy: \(x\in\left\{3.8;1.2\right\}\)
b) Ta có: \(1.6-\left|x-0.2\right|=0\)
\(\Leftrightarrow\left|x-0.2\right|=1.6\)
\(\Leftrightarrow\left[{}\begin{matrix}x-0.2=1.6\\x-0.2=-1.6\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=1.8\\x=-1.4\end{matrix}\right.\)
Vậy: \(x\in\left\{1.8;-1.4\right\}\)
c) Ta có: \(13^x=169\)
\(\Leftrightarrow13^x=13^2\)
\(\Leftrightarrow x=2\)
Vậy: x=2
d) Ta có: \(\dfrac{-2}{x}=\dfrac{-x}{\dfrac{8}{25}}\)
\(\Leftrightarrow\dfrac{2}{x}=\dfrac{x}{\dfrac{8}{25}}\)
\(\Leftrightarrow x^2=\dfrac{16}{25}\)
hay \(x\in\left\{\dfrac{4}{5};-\dfrac{4}{5}\right\}\)
Vậy: \(x\in\left\{\dfrac{4}{5};-\dfrac{4}{5}\right\}\)
\(|2,5-x|=1,3\)
\(\Rightarrow2,5-x=1,3\) hoặc -(2,5-x)=1,3
=>x=2,5-1,3 x-2,5=1,3
=>x=1,2 x=1,3+2,5=3,8
Vậy \(x\in\left\{1,2;3,8\right\}\)
\(1,6-|x-0,2|=0\Rightarrow|x-0,2|=1,6\)
=> x-0,2=1,6 hoặc -(x-0,2)=1,6
=>x=1,6+0,2 0,2-x=1,6
=>x=3,8 x=0,2-1,6=-1,4
Vậy \(x\in\left\{3,8;-1,4\right\}\)
\(13^x=169\Rightarrow13^x=13^2\Rightarrow x=2\)
\(\dfrac{-2}{x}=\dfrac{-x}{\dfrac{8}{25}}\Rightarrow-2\times\dfrac{8}{25}=-x\times x\Rightarrow\dfrac{-16}{25}=-x^2\Rightarrow\dfrac{16}{25}=x^2\Rightarrow x^2=\left(\dfrac{4}{5}\right)^2=\left(-\dfrac{4}{5}\right)^2\)
\(\Rightarrow x=\dfrac{4}{5}\) hoặc \(x=-\dfrac{4}{5}\)
cần gấp , giúp mình với:
\(\dfrac{1}{21}+\dfrac{1}{28}+\dfrac{1}{36}+...+\dfrac{1}{465}\)
M = 1/21 + 1/28+1/36+...+1/465
= 2/42+2/56+2/72+...+2/930
= 2.( 1/6.7 + 1/7.8 + 1/ 7.9 + ... + 1/30.31)
= 2.( 1/6-1/7+1/7-1/8+...+1/30-1/31)
= 2.(1/6 - 1/31) = 2.25/186 = 25/92
1.cho x > 0. tìm GTNN của A = \(\dfrac{3x^4+16}{x^3}\)
2. cho x,y,z > 0 thỏa mãn x+y+z=2. tìm GTNN của biểu thức:
P=\(\dfrac{x^2}{y+z}+\dfrac{y^2}{z+x}+\dfrac{z^2}{x+y}\)
giúp mình với ạ, mình đang cần gấp trong tối nay ạ.
12 x (\(\dfrac{29292929}{56565656}\)+\(\dfrac{66666}{77777}\))
Giúp mình với,mình cần gấp
\(12.\left(\dfrac{29292929}{56565656}+\dfrac{66666}{77777}\right)=12.\left(\dfrac{29}{56}+\dfrac{6}{7}\right)=12.\left(\dfrac{29}{56}+\dfrac{48}{56}\right)=12.\dfrac{77}{56}=\dfrac{33}{2}\)
\(12.\left(\dfrac{29292929}{56565656}+\dfrac{66666}{77777}\right)=12.\left(\dfrac{29.1010101}{56.1010101}+\dfrac{6.11111}{7.11111}\right)=12.\left(\dfrac{29}{56}+\dfrac{6}{7}\right)=12.\dfrac{11}{8}=\dfrac{33}{2}\)
\(\dfrac{7}{8}+x=\dfrac{3}{5}\)
ai giúp mình nhanh với mình cần gấp
\(x=\dfrac{3}{5}-\dfrac{7}{8}=-\dfrac{11}{40}\)
\(\dfrac{7}{8}+x=\dfrac{3}{5}\)
\(x=\dfrac{3}{5}-\dfrac{7}{8}\)
\(x=-\dfrac{11}{40}\)