x - 25% . x = \(\frac{1}{2}\)
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Phương trình chính tắc của elip là: c) \(\frac{{{x^2}}}{{64}} + \frac{{{y^2}}}{{25}} = 1\).
a) Không là PTCT vì a =b =8
b) Không là PTCT
d) Không là PTCT vì a =5 < b =8.
mk sắp phải đi học rồi các bạn giúp mình với có đc ko mk nhớ sẽ đền đáp công ơn của bạn
ĐKXĐ:...
\(\left(\frac{\sqrt{x}\left(\sqrt{x}-5\right)}{\left(\sqrt{x}-5\right)\left(\sqrt{x}+5\right)}-1\right):\left(\frac{25-x}{\left(\sqrt{x}-3\right)\left(\sqrt{x}+5\right)}-\frac{\left(\sqrt{x}+3\right)\left(\sqrt{x}-3\right)}{\left(\sqrt{x}-3\right)\left(\sqrt{x}+5\right)}+\frac{\left(\sqrt{x}-5\right)\left(\sqrt{x}+5\right)}{\left(\sqrt{x}-3\right)\left(\sqrt{x}+5\right)}\right)\)
\(=\left(\frac{\sqrt{x}-\sqrt{x}-5}{\sqrt{x}+5}\right):\left(\frac{25-x-x+9+x-25}{\left(\sqrt{x}-3\right)\left(\sqrt{x}+5\right)}\right)=\frac{-5}{\left(\sqrt{x}+5\right)}.\frac{\left(\sqrt{x}-3\right)\left(\sqrt{x}+5\right)}{\left(9-x\right)}\)
\(=\frac{5\left(\sqrt{x}-3\right)}{\left(\sqrt{x}+3\right)\left(\sqrt{x}-3\right)}=\frac{5}{\sqrt{x}+3}\)
ĐKXĐ \(x\ne0,-1,-2,...,-100\)
\(\frac{1}{x^2+x}+\frac{1}{x^2+3x+2}+...+\frac{1}{x^2+199x+9900}=\frac{25}{51}\)
\(\Leftrightarrow\frac{1}{x\left(x+1\right)}+\frac{1}{x^2+x+2x+2}+...+\frac{1}{x^2+99x+100x+9900}=\frac{25}{51}\)
\(\Leftrightarrow\frac{1}{x\left(x+1\right)}+\frac{1}{x\left(x+1\right)+2\left(x+1\right)}+....+\frac{1}{x\left(x+99\right)+100\left(x+99\right)}=\frac{25}{51}\)
\(\Leftrightarrow\frac{1}{x\left(x+1\right)}+\frac{1}{\left(x+1\right)\left(x+2\right)}+...+\frac{1}{\left(x+99\right)\left(x+100\right)}=\frac{25}{21}\)
\(\Leftrightarrow\frac{1}{x}-\frac{1}{x+1}+\frac{1}{x+1}-\frac{1}{x+2}+...+\frac{1}{x+99}-\frac{1}{x+100}=\frac{25}{21}\)
\(\Leftrightarrow\frac{1}{x}-\frac{1}{x+100}=\frac{25}{21}\)
\(\Leftrightarrow\frac{x+100-x}{x\left(x+100\right)}=\frac{25}{21}\)
\(\Leftrightarrow\frac{100}{x\left(x+100\right)}=\frac{25}{21}\)
\(\Leftrightarrow25x^2+2500x=2100\)
\(\Leftrightarrow x^2+100x-84=0\)
\(\Leftrightarrow x^2+2.x.50+50^2-50^2-84=0\)
\(\Leftrightarrow\left(x+50\right)^2-2584=0\)
\(\Leftrightarrow\left(x+50-2\sqrt{646}\right)\left(x+50+2\sqrt{646}\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x=-50+2\sqrt{646}\\x=-50-2\sqrt{646}\end{cases}}\)
Vậy ...
\(\left(x+\frac{1}{2}\right)\cdot\left(\frac{2}{3}-2x\right)=0\)
TH1 : \(\Rightarrow x+\frac{1}{2}=0\)
\(x=0-\frac{1}{2}\)
\(x=\frac{-1}{2}\)
TH2 : \(\Rightarrow\frac{2}{3}-2x=0\)
\(2x=0+\frac{2}{3}=\frac{2}{3}\)
\(x=\frac{2}{3}\div2=\frac{1}{3}\)
\(\Rightarrow x=\frac{-1}{2};\frac{1}{3}\)
\(\left(x+\frac{1}{5}\right)^2+\frac{17}{25}=\frac{26}{25}\)
\(\left(x+\frac{1}{5}\right)^2=\frac{26}{25}-\frac{17}{25}\)
\(\left(x+\frac{1}{5}\right)^2=\frac{9}{25}=\left(\frac{3}{5}\right)^2\)
\(x=\frac{3}{5}^2-\frac{1}{5}^2\)
\(x=\frac{2}{5}\)
\(\frac{x+5}{x^2-5x}-\frac{x+25}{2x^2-50}=\frac{x-5}{2x^2+10x}\)
\(\Leftrightarrow\frac{x+5}{x\left(x-5\right)}-\frac{x+25}{2\left(x^2-25\right)}=\frac{x-5}{2x\left(x+5\right)}\)
\(\Leftrightarrow\frac{2\left(x+5\right)^2}{2x\left(x-5\right)\left(x+5\right)}-\frac{x\left(x+25\right)}{2x\left(x-5\right)\left(x+5\right)}=\frac{\left(x-5\right)^2}{2x\left(x+5\right)\left(x-5\right)}\)
\(\Rightarrow2\left(x^2+10x+25\right)-x^2-25x=x^2-10x+25\)
\(\Leftrightarrow2x^2+20x+50-x^2-25x-x^2+10x-25=0\)
\(\Leftrightarrow5x+25=0\)
\(\Leftrightarrow x=-5\)
\(\frac{x+1}{x-1}-\frac{x-1}{x+1}=\frac{16}{x^2-1}\)
\(\Leftrightarrow\frac{\left(x+1\right)^2}{\left(x-1\right)\left(x+1\right)}-\frac{\left(x-1\right)^2}{\left(x+1\right)\left(x-1\right)}=\frac{16}{\left(x-1\right)\left(x+1\right)}\)
\(\Rightarrow\left(x+1-x+1\right)\left(x+1+x-1\right)=16\)
\(\Leftrightarrow2.2x=16\)
\(\Leftrightarrow4x=16\)
\(\Leftrightarrow x=4\)
x*75%=1/2
X=1/2:75%
X=2/3
nhớ k nhé
\(x-25\%.x=\frac{1}{2}\)
\(x.\left(1-\frac{1}{4}\right)=\frac{1}{2}\)( Do 25% = \(\frac{1}{4}\))
\(x.\frac{3}{4}=\frac{1}{2}\)
\(x=\frac{1}{2}:\frac{3}{4}=\frac{2}{3}\)