\(\left(4x-10\right)\left(24+5x\right)=0\)

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4 tháng 5 2017

a) \(\left(4x-10\right)\left(24+5x\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}4x-10=0\\24+5x=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\dfrac{10}{4}=\dfrac{5}{2}\\x=-\dfrac{24}{5}\end{matrix}\right.\)

Vậy \(S=\left\{-\dfrac{24}{5};\dfrac{5}{2}\right\}\)

b) \(\left(3.5-7x\right)\left(0.1x+2.3\right)=0\)

\(\Rightarrow\left[{}\begin{matrix}3.5-7x=0\\0.1x+2.3=0\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\dfrac{3.5}{7}=\dfrac{1}{2}\\x=-\dfrac{2.3}{0.1}=-23\end{matrix}\right.\)

Vậy \(S=\left\{-23;\dfrac{1}{2}\right\}\)

2 tháng 3 2019

a)\(\left(x^2+1\right)\left(x^2-4x+4\right)=0\Leftrightarrow\orbr{\begin{cases}x^2+1=0\\x^2-4x+4=0\end{cases}\Rightarrow\orbr{\begin{cases}x^2=-1\left(vn\right)\\\left(x-2\right)^2=0\end{cases}\Rightarrow}x=2}\)

b)\(\left(3x-2\right)\left(\frac{2x+6}{7}-\frac{4x-3}{5}\right)=0\\ \Rightarrow\left(3x-2\right)\left(\frac{10x+30-28x+21}{35}\right)=0\)

\(\Rightarrow\left(3x-2\right)\left(\frac{-18x+51}{35}\right)=0\Rightarrow\orbr{\begin{cases}x=\frac{2}{3}\\x=\frac{17}{6}\end{cases}}\)

c)\(\left(3,3-11x\right)\left(\frac{21x+6+10-30x}{15}\right)=0\Leftrightarrow\orbr{\begin{cases}x=\frac{3}{10}\\x=\frac{16}{9}\end{cases}}\)

b: \(\Leftrightarrow\dfrac{7x+10}{x+1}\left(x^2-x-2-2x^2+3x+5\right)=0\)

\(\Leftrightarrow\left(7x+10\right)\left(-x^2+2x+3\right)=0\)

\(\Leftrightarrow\left(7x+10\right)\left(x^2-2x-3\right)=0\)

=>(7x+10)(x-3)=0

hay \(x\in\left\{-\dfrac{10}{7};3\right\}\)

d: \(\Leftrightarrow\dfrac{13}{2x^2+7x-6x-21}+\dfrac{1}{2x+7}-\dfrac{6}{\left(x-3\right)\left(x+3\right)}=0\)

\(\Leftrightarrow\dfrac{13}{\left(2x+7\right)\left(x-3\right)}+\dfrac{1}{\left(2x+7\right)}-\dfrac{6}{\left(x-3\right)\left(x+3\right)}=0\)

\(\Leftrightarrow26x+91+x^2-9-12x-14=0\)

\(\Leftrightarrow x^2+14x+68=0\)

hay \(x\in\varnothing\)

b: =>(2x-1)(2x-1+4-2x)=0

=>3(2x-1)=0

=>2x-1=0

=>x=1/2

c: =>(x+1)(x^2-x+1)-x(x+1)=0

=>(x+1)(x-1)^2=0

=>x=1 hoặc x=-1

e: =>(2x-1)(2x+1)=0

=>x=1/2 hoặc x=-1/2

h: =>x[(x^2-5)^2-4]=0

=>x(x^2-7)(x^2-3)=0

=>\(x\in\left\{0;\pm\sqrt{7};\pm\sqrt{3}\right\}\)

k: =>(x-1)(5x+3-3x+8)=0

=>(x-1)(2x+11)=0

=>x=1 hoặc x=-11/2

l: =>x^2(x+1)+(x+1)=0

=>(x+1)(x^2+1)=0

=>x+1=0

=>x=-1

1: =>2x-5=4 hoặc 2x-5=-4

=>2x=9 hoặc 2x=1

=>x=9/2hoặc x=1/2

2: \(\Leftrightarrow\left|2x+1\right|=\dfrac{3}{4}-\dfrac{7}{8}=\dfrac{-1}{8}\)(vô lý)

3: \(\Leftrightarrow\left|5x-3\right|=x+5\)

\(\Leftrightarrow\left\{{}\begin{matrix}x>=-5\\\left(5x-3-x-5\right)\left(5x-3+x+5\right)=0\end{matrix}\right.\)

\(\Leftrightarrow\left\{{}\begin{matrix}x>=-5\\\left(4x-8\right)\left(6x+2\right)=0\end{matrix}\right.\Leftrightarrow x\in\left\{2;-\dfrac{1}{3}\right\}\)