\(\dfrac{x+2}{0,5}=\dfrac{2x+1}{2}\)
HELP ME!!!
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
Tính M = \(1+\frac{1}{2}+\frac{1}{2^2}+...+\frac{1}{2^{100}}\)
a/ \(\dfrac{x-1}{5}=\dfrac{1-2x}{3}\)
\(\Leftrightarrow3\left(x-1\right)=5\left(1-2x\right)\)
\(\Leftrightarrow3x-3=5-10x\)
\(\Leftrightarrow3x+10x=5+3\)
\(\Leftrightarrow13x=8\)
\(\Leftrightarrow x=\dfrac{8}{13}\)
Vậy ...
b/ \(\dfrac{3-\left|x\right|}{5}=1\dfrac{1}{2}:\dfrac{-6}{5}\)
\(\Leftrightarrow\dfrac{3-\left|x\right|}{5}=\dfrac{-5}{4}\)
\(\Leftrightarrow\left(3-\left|x\right|\right)4=5.\left(-5\right)\)
\(\Leftrightarrow\left(3-\left|x\right|\right).4=-25\)
\(\Leftrightarrow3-\left|x\right|=-6,25\)
\(\Leftrightarrow\left|x\right|=-3,25\)
\(\Leftrightarrow x\in\varnothing\)
\(\dfrac{x-1}{5}=\dfrac{1-2x}{3}\Rightarrow3x-3=5-10x\)
Áp dụng tính chất chuyển quế đổi giấu
3x+10x=5+3=8
13x=8
\(\Rightarrow\dfrac{8}{13}\)
b)\(\dfrac{3-|x|}{5}=1\dfrac{1}{2}chia\dfrac{-6}{5}=\dfrac{-5}{4}\)
3-/x/=5chia\(\dfrac{-5}{4}\)=-4
/x/=-4+3=-1
Mà /x/\(\ge0\Rightarrow x\in\varnothing\)
Tick em nha
a: \(=\dfrac{4xy+x^2-2xy+y^2}{2\left(x+y\right)\left(x-y\right)}\cdot\dfrac{2x}{x+y}-\dfrac{y}{x-y}\)
\(=\dfrac{x}{x-y}-\dfrac{y}{x-y}=1\)
b: \(=\dfrac{x^2+x-2-2x^2-2x}{\left(x-1\right)\left(x+1\right)}\cdot\dfrac{3\left(x+1\right)}{x}+\dfrac{4x^2+x+7}{x\left(x-1\right)}\)
\(=\dfrac{-x^2-x-2}{\left(x-1\right)}\cdot\dfrac{3}{x}+\dfrac{4x^2+x+7}{x\left(x-1\right)}\)
\(=\dfrac{4x^2+x+7-3x^2-3x-6}{x\left(x-1\right)}=\dfrac{x^2-2x+1}{x\left(x-1\right)}=\dfrac{x-1}{x}\)
c: \(=\dfrac{1}{x+4}-\dfrac{1}{x+5}+\dfrac{1}{x+5}-\dfrac{1}{x+6}+\dfrac{1}{x+6}-\dfrac{1}{x+7}\)
\(=\dfrac{x+7-x-4}{\left(x+7\right)\left(x+4\right)}=\dfrac{3}{\left(x+4\right)\left(x+7\right)}\)
ÁP dụng cái bất đẳng thức j j đó
mk có xem làm ở đâu rùi nhưng chưa học nên ko bt giải
\(\dfrac{x+2}{0,5}=\dfrac{2x+1}{2}\)
\(\Leftrightarrow\left(x+2\right).2=\left(2x+1\right).0,5\)
\(\Leftrightarrow2x+4=x+0,5\)
\(\Leftrightarrow x=-3,5\)
Vậy...
\(\dfrac{x+2}{0,5}=\dfrac{2x+1}{2}\)
\(\Leftrightarrow\dfrac{4.\left(x+2\right)}{2}=\dfrac{2x+1}{2}\)
\(\Rightarrow4x+8=2x+1\)
\(\Leftrightarrow4x-2x=1-8\)
\(\Leftrightarrow2x=-7\)
\(\Leftrightarrow x=\dfrac{-7}{2}\)
Vậy \(x=\dfrac{-7}{2}\)