tô thị cẩm tú

a. 6x-4=5x

b.\(\dfrac{2x+3}{3}\) =\(\dfrac{5-4x}{2}\)

c.(x+7) (x-10) =0

d. \(\dfrac{2}{x-3}\)+\(\dfrac{3}{x+3}\)=\(\dfrac{3x+5}{x^2-9}\)

ILoveMath
5 tháng 3 2022 lúc 20:39

\(a,6x-4=5x\\ \Leftrightarrow x-4=0\\ \Leftrightarrow x=4\\ b,\dfrac{2x+3}{3}=\dfrac{5-4x}{2}\\ \Leftrightarrow2\left(2x+3\right)=3\left(5-4x\right)\\ \Leftrightarrow4x+6=15-12x\\ \Leftrightarrow16x-9=0\\ \Leftrightarrow x=\dfrac{9}{16}\\ c,\left(x+7\right)\left(x-10\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x+7=0\\x-10=0\end{matrix}\right.\\ \Leftrightarrow\left[{}\begin{matrix}x=-7\\x=10\end{matrix}\right.\)

d, ĐKXĐ:\(x\ne\pm3\)

\(\dfrac{2}{x-3}+\dfrac{3}{x+3}=\dfrac{3x+5}{x^2-9}\\ \Leftrightarrow\dfrac{2\left(x+3\right)}{\left(x+3\right)\left(x-3\right)}+\dfrac{3\left(x-3\right)}{\left(x+3\right)\left(x-3\right)}-\dfrac{3x+5}{\left(x+3\right)\left(x-3\right)}=0\\ \Leftrightarrow\dfrac{2x+6+3x-9-3x-5}{\left(x+3\right)\left(x-3\right)}=0\\ \Rightarrow2x-8=0\\ \Leftrightarrow x=4\left(tm\right)\)

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Nguyễn Ngọc Huy Toàn
5 tháng 3 2022 lúc 20:41

a.6x-4=5x <=> x=4

b.\(\dfrac{2x+3}{3}=\dfrac{5-4x}{2}\)

\(\Leftrightarrow\dfrac{2\left(2x+3\right)}{6}=\dfrac{3\left(5-4x\right)}{6}\)

\(\Leftrightarrow2\left(2x+3\right)=3\left(5-4x\right)\)

\(\Leftrightarrow4x+6=15-12x\)

\(\Leftrightarrow16x=11\)

\(\Leftrightarrow x=\dfrac{11}{16}\)

c.(x+7)(x-10)=0

\(\Leftrightarrow\left[{}\begin{matrix}x+7=0\\x-10=0\end{matrix}\right.\) \(\Leftrightarrow\left[{}\begin{matrix}x=-7\\x=10\end{matrix}\right.\)

d.\(ĐK:x\ne\pm3\)

\(\Rightarrow\dfrac{2}{x-3}+\dfrac{3}{x+3}=\dfrac{3x+5}{\left(x-3\right)\left(x+3\right)}\)

\(\Leftrightarrow\dfrac{2\left(x+3\right)+3\left(x-3\right)}{\left(x-3\right)\left(x+3\right)}=\dfrac{3x+5}{\left(x-3\right)\left(x+3\right)}\)

\(\Leftrightarrow2\left(x+3\right)+3\left(x-3\right)=3x+5\)

\(\Leftrightarrow2x+6+3x-9-3x-5=0\)

\(\Leftrightarrow2x-8=0\)

\(\Leftrightarrow2x=8\)

\(\Leftrightarrow x=4\left(tm\right)\)

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Nguyễn Huy Tú ( ✎﹏IDΣΛ...
5 tháng 3 2022 lúc 20:37

a, \(6x-5x=4\Leftrightarrow x=4\)

b, \(4x+6=15-12x\Leftrightarrow16x=9\Leftrightarrow x=\dfrac{9}{16}\)

c, \(\left[{}\begin{matrix}x+7=0\\x-10=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-7\\x=10\end{matrix}\right.\)

d, đk : x khác -3 ; 3 

\(2x+6+3x-9=3x+5\Leftrightarrow2x=8\Leftrightarrow x=4\left(tmđk\right)\)

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hưng phúc
5 tháng 3 2022 lúc 20:41

\(a.6x-4=5x\)

\(\Leftrightarrow x=4\)

\(b.\dfrac{2x+3}{3}=\dfrac{5-4x}{2}\)

\(\Leftrightarrow\dfrac{4x+6}{6}=\dfrac{15-12x}{6}\)

\(\Leftrightarrow4x+6=15-12x\)

\(\Leftrightarrow16x=9\)

\(\Leftrightarrow x=\dfrac{9}{16}\)

\(c.\left(x+7\right)\left(x-10\right)=0\)

\(\Leftrightarrow\left[{}\begin{matrix}x+7=0\\x-10=0\end{matrix}\right.\)

\(\Leftrightarrow\left[{}\begin{matrix}x=-7\\x=10\end{matrix}\right.\)

\(d.\dfrac{2}{x-3}+\dfrac{3}{x+3}=\dfrac{3x+5}{x^2-9}\left(đk:x\ne\pm3\right)\)

\(\Leftrightarrow\dfrac{2x+6}{x^2-9}+\dfrac{3x-9}{x^2-9}=\dfrac{3x+5}{x^2-9}\)

\(\Rightarrow2x+6+3x-9=3x+5\)

\(\Leftrightarrow2x=8\)

\(\Leftrightarrow x=4\left(tm\right)\)

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