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14 tháng 3 2020

phá ngoặc rồi giải?

(x3 + x2) + (x2 + x) = 0

<=> x+ x2 + x+ x = 0

<=> x3 + 2x2 + x = 0

<=> x(x + 1)(x + 1) = 0

<=> x = 0 hoặc x + 1 = 0

<=> x = 0 hoặc x = -1

26 tháng 12 2021

a: \(\Leftrightarrow\left[{}\begin{matrix}3x+2=4\\3x+2=-4\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{2}{3}\\x=-2\end{matrix}\right.\)

Ta có: \(\dfrac{x-25}{75}+\dfrac{x-15}{85}+\dfrac{x-5}{95}+\dfrac{x-145}{15}=0\)

\(\Leftrightarrow\dfrac{x-25}{75}-1+\dfrac{x-15}{85}-1+\dfrac{x-5}{95}-1+\dfrac{x-145}{15}+3=0\)

\(\Leftrightarrow\dfrac{x-100}{75}+\dfrac{x-100}{85}+\dfrac{x-100}{95}+\dfrac{x-100}{15}=0\)

\(\Leftrightarrow\left(x-100\right)\left(\dfrac{1}{75}+\dfrac{1}{85}+\dfrac{1}{95}+\dfrac{1}{15}\right)=0\)

mà \(\dfrac{1}{75}+\dfrac{1}{85}+\dfrac{1}{95}+\dfrac{1}{15}>0\)

nên x-100=0

hay x=100

Vậy: S={100}

7 tháng 3 2021

⇔ 4X - 3304/323 = 0

⇔ X=3304/323/4

⇔ X=826/323

5 tháng 9 2021

\(\left(x^2-9\right)^2-\left(x-3\right)^2=0\)

\(\Leftrightarrow\left(x-3\right)^2\left(x+3\right)^2-\left(x-3\right)^2=0\)

\(\Leftrightarrow\left(x-3\right)^2\left[\left(x+3\right)^2-1\right]=0\)

\(\Leftrightarrow\left[{}\begin{matrix}\left(x-3\right)^2=0\\\left(x+3\right)^2=1\end{matrix}\right.\)\(\Leftrightarrow\left[{}\begin{matrix}x-3=0\\x+3=1\\x+3=-1\end{matrix}\right.\)\(\Leftrightarrow\left[{}\begin{matrix}x=3\\x=-2\\x=-4\end{matrix}\right.\)

5 tháng 9 2021

cảm ơn nhìu ạ!!!!

 

 

a)Ta có: \(\dfrac{x+3}{x+1}+\dfrac{1}{3}\ge0\)

\(\Leftrightarrow\dfrac{3x+9+x+1}{3\left(x+1\right)}\ge0\)

\(\Leftrightarrow\dfrac{4x+10}{3x+3}\ge0\)

\(\Leftrightarrow\left[{}\begin{matrix}x+1>0\\4x+10\le0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x>-1\\x\le-\dfrac{5}{2}\end{matrix}\right.\)

b) Ta có: \(\dfrac{x+2}{x+3}+\dfrac{1}{3}\le0\)

\(\Leftrightarrow\dfrac{3x+6+x+3}{3\left(x+3\right)}\le0\)

\(\Leftrightarrow\dfrac{4x+9}{3x+9}\le0\)

\(\Leftrightarrow\left\{{}\begin{matrix}3x+9>0\\4x+9\le0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}x>-3\\x\le-\dfrac{9}{4}\end{matrix}\right.\Leftrightarrow-3< x\le-\dfrac{9}{4}\)

13 tháng 7 2021

a)\(\dfrac{x+3}{x+1}\ge-\dfrac{1}{3}\left(x\ne-1\right)\)

\(\Leftrightarrow\dfrac{x+3}{x+1}+\dfrac{1}{3}\ge0\)

\(\Leftrightarrow\dfrac{3x+9+x+1}{3x+3}\ge0\)

\(\Leftrightarrow\dfrac{4x+10}{3x+3}\ge0\)

\(\Leftrightarrow\left[{}\begin{matrix}\left\{{}\begin{matrix}4x+10\ge0\\3x+3>0\end{matrix}\right.\\\left\{{}\begin{matrix}4x+10\le0\\3x+3< 0\end{matrix}\right.\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}\left\{{}\begin{matrix}x\ge-\dfrac{5}{2}\\x>-1\end{matrix}\right.\\\left\{{}\begin{matrix}x\le\dfrac{-5}{2}\\x< -1\end{matrix}\right.\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x>-1\\x\le\dfrac{-5}{2}\end{matrix}\right.\)

 b) \(\dfrac{x+2}{x+3}\le-\dfrac{1}{3}\left(x\ne-3\right)\)

\(\dfrac{x+2}{x+3}+\dfrac{1}{3}\le0\)

\(\Leftrightarrow\dfrac{3x+6+x+3}{3x+9}\le0\)

\(\Leftrightarrow\dfrac{4x+9}{3x+9}\le0\)

\(\Leftrightarrow\left[{}\begin{matrix}\left\{{}\begin{matrix}4x+9\ge0\\3x+9< 0\end{matrix}\right.\\\left\{{}\begin{matrix}4x+9\le0\\3x+9>0\end{matrix}\right.\end{matrix}\right.\)

\(\left[{}\begin{matrix}\left\{{}\begin{matrix}x\ge-\dfrac{9}{4}\\x< -3\end{matrix}\right.\\\left\{{}\begin{matrix}x\le-\dfrac{9}{4}\\x>-3\end{matrix}\right.\end{matrix}\right.\)    

TH1: loại

TH2: TM

Vậy no của BPT là :\(-\dfrac{9}{4}\ge x>-3\)

chúc bạn học tốt

25 tháng 2 2022

a,\(\left(x-4-5\right)\left(x-4+5\right)=0\Leftrightarrow\left(x-9\right)\left(x+1\right)=0\Leftrightarrow x=9;x=-1\)

b, \(\left(x-3-x-1\right)\left(x-3+x+1\right)=0\Leftrightarrow2x-2=0\Leftrightarrow x=1\)

c, \(\left(x^2-4\right)\left(2x-3\right)-\left(x^2-4\right)\left(x-1\right)=0\)

\(\Leftrightarrow\left(x^2-4\right)\left(2x-3-x+1\right)=0\Leftrightarrow\left(x-2\right)\left(x+2\right)\left(x-2\right)=0\Leftrightarrow x=-2;x=2\)

d, \(\left(3x-7\right)^2-\left(2x+2\right)^2=0\Leftrightarrow\left(3x-7-2x-2\right)\left(3x-7+2x+2\right)=0\)

\(\Leftrightarrow\left(x-9\right)\left(5x-5\right)=0\Leftrightarrow x=1;x=9\)

25 tháng 2 2022

a) Ta có: 4x-20=0

⇔4x=20

hay x=5

Vậy: S={5}

b) Ta có: 2x+x+12=0

⇔3x+12=0

⇔3x=−12

hay x=-4

c: \(\Leftrightarrow\left[{}\begin{matrix}x=\sqrt{7}\\x=-\sqrt{7}\\x=-5\\x=5\end{matrix}\right.\)

3 tháng 12 2021

mik lớp 6 bạn