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Question

Tìm x, biết:a)−$\dfrac{3}{5}$.x=$\dfrac{12}{25}$;b)$\dfrac{3}{5}$x−$\dfrac{3}{4}$=−1$\dfrac{1}{2}$;c)$\dfrac{2}{5}$+$\dfrac{3}{5}$:x=0,5;d)$\dfrac{3}{4}$−(x−$\dfrac{1}{2}$)=1\(\dfrac...

Vanh Nek · Accepted Answer

a)$-\dfrac{3}{5}.x=\dfrac{12}{25}$$x=\dfrac{12}{25}:\left(-\dfrac{3}{5}\right)$$x=\dfrac{12}{25}.\dfrac{-5}{3}$$x=\dfrac{-4}{5}$b)$\dfrac{3}{5}x-\dfrac{3}{4}=-1\dfrac{1}{2}$$\dfrac{3}{5}x-\dfrac{3}{4}=\dfrac{-3}{2}$$\dfrac{3}{5}x=\dfrac{-3}{2}+\dfrac{3}{4}$$\dfrac{3}{5}x=\dfrac{-6}{4}+\dfrac{3}{4}$$\dfrac{3}{5}x=\dfrac{-3}{4}$$x=\dfrac{-3}{4}:\dfrac{3}{5}$$x=\dfrac{-3}{4}.\dfrac{5}{3}$$x=\dfrac{-5}{4}$c)$\dfrac{2}{5}+\dfrac{3}{5}:x=0,5$$\dfrac{2}{5}+\dfrac{3}{5}:x=\dfrac{1}{2}$$\dfrac{3}{5}:x=\dfrac{1}{2}-\dfrac{2}{5}$$\dfrac{3}{5}:x=\dfrac{5}{10}-\dfrac{4}{10}$$\dfrac{3}{5}:x=\dfrac{1}{10}$$x=\dfrac{3}{5}:\dfrac{1}{10}$$x=\dfrac{3}{5}.\dfrac{10}{1}$$x=6$d)$\dfrac{3}{4}-\left(x-\dfrac{1}{2}\right)=1\dfrac{2}{3}$$\dfrac{3}{4}-\left(x-\dfrac{1}{2}\right)=\dfrac{5}{3}$$x-\dfrac{1}{2}=\dfrac{3}{4}-\dfrac{5}{3}$$x-\dfrac{1}{2}=\dfrac{9}{12}-\dfrac{20}{12}$$x-\dfrac{1}{2}=\dfrac{-11}{12}$$x=\dfrac{-11}{12}+\dfrac{1}{2}$$x=\dfrac{-11}{12}+\dfrac{6}{12}$$x=\dfrac{-5}{12}$e)$2\dfrac{2}{15}:\left(\dfrac{1}{3}-5x\right)=-2\dfrac{2}{5}$$\dfrac{32}{15}:\left(\dfrac{1}{3}-5x\right)=\dfrac{-12}{5}$$\dfrac{1}{3}-5x=\dfrac{32}{15}:\dfrac{-12}{5}$$\dfrac{1}{3}-5x=\dfrac{32}{15}.\dfrac{-5}{12}$$\dfrac{1}{3}-5x=\dfrac{-8}{9}$$5x=\dfrac{1}{3}-\dfrac{-8}{9}$$5x=\dfrac{3}{9}+\dfrac{8}{9}$$5x=\dfrac{11}{9}$$x=\dfrac{11}{9}:5$$x=\dfrac{11}{45}$g)$x^2+\dfrac{1}{9}=\dfrac{5}{3}:3$$x^2+\dfrac{1}{9}=\dfrac{5}{9}$$x^2=\dfrac{5}{9}-\dfrac{1}{9}$$x^2=\dfrac{4}{9}$$x^2=\left(\dfrac{2}{3}\right)^2$ hoặc $x^2=\left(-\dfrac{2}{3}\right)^2$Nên $\Rightarrow x=\dfrac{2}{3}$ hoặc $x=-\dfrac{2}{3}$Câu trả lời: a)$-\dfrac{3}{5}.x=\dfrac{12}{25}$$x=\dfrac{12}{25}:\left(-\dfrac{3}{5}\right)$$x=\dfrac{12}{25}.\dfrac{-5}{3}$$x=\dfrac{-4}{5}$b)$\dfrac{3}{5}x-\dfrac{3}{4}=-1\dfrac{1}{2}$$\dfrac{3}{5}x-\dfrac{3}{4}=\dfrac{-3}{2}$$\dfrac{3}{5}x=\dfrac{-3}{2}+\dfrac{3}{4}$$\dfrac{3}{5}x=\dfrac{-6}{4}+\dfrac{3}{4}$$\dfrac{3}{5}x=\dfrac{-3}{4}$$x=\dfrac{-3}{4}:\dfrac{3}{5}$$x=\dfrac{-3}{4}.\dfrac{5}{3}$$x=\dfrac{-5}{4}$c)$\dfrac{2}{5}+\dfrac{3}{5}:x=0,5$$\dfrac{2}{5}+\dfrac{3}{5}:x=\dfrac{1}{2}$$\dfrac{3}{5}:x=\dfrac{1}{2}-\dfrac{2}{5}$$\dfrac{3}{5}:x=\dfrac{5}{10}-\dfrac{4}{10}$$\dfrac{3}{5}:x=\dfrac{1}{10}$$x=\dfrac{3}{5}:\dfrac{1}{10}$$x=\dfrac{3}{5}.\dfrac{10}{1}$$x=6$d)$\dfrac{3}{4}-\left(x-\dfrac{1}{2}\right)=1\dfrac{2}{3}$$\dfrac{3}{4}-\left(x-\dfrac{1}{2}\right)=\dfrac{5}{3}$$x-\dfrac{1}{2}=\dfrac{3}{4}-\dfrac{5}{3}$$x-\dfrac{1}{2}=\dfrac{9}{12}-\dfrac{20}{12}$$x-\dfrac{1}{2}=\dfrac{-11}{12}$$x=\dfrac{-11}{12}+\dfrac{1}{2}$$x=\dfrac{-11}{12}+\dfrac{6}{12}$$x=\dfrac{-5}{12}$e)$2\dfrac{2}{15}:\left(\dfrac{1}{3}-5x\right)=-2\dfrac{2}{5}$$\dfrac{32}{15}:\left(\dfrac{1}{3}-5x\right)=\dfrac{-12}{5}$$\dfrac{1}{3}-5x=\dfrac{32}{15}:\dfrac{-12}{5}$$\dfrac{1}{3}-5x=\dfrac{32}{15}.\dfrac{-5}{12}$$\dfrac{1}{3}-5x=\dfrac{-8}{9}$$5x=\dfrac{1}{3}-\dfrac{-8}{9}$$5x=\dfrac{3}{9}+\dfrac{8}{9}$$5x=\dfrac{11}{9}$$x=\dfrac{11}{9}:5$$x=\dfrac{11}{45}$g)$x^2+\dfrac{1}{9}=\dfrac{5}{3}:3$$x^2+\dfrac{1}{9}=\dfrac{5}{9}$$x^2=\dfrac{5}{9}-\dfrac{1}{9}$$x^2=\dfrac{4}{9}$$x^2=\left(\dfrac{2}{3}\right)^2$ hoặc $x^2=\left(-\dfrac{2}{3}\right)^2$Nên $\Rightarrow x=\dfrac{2}{3}$ hoặc $x=-\dfrac{2}{3}$

le phong · Answer

a) x=−35−35x=3535x=3434−34−34x=3535x=3535:x=0,5-3535:x=3535:1212)=2323(x-3434-11212)=−1112−1112+−1712−1712e) 215215:(-21313-5x=1313-119119x=11451145g) x2+5959x2=1919x2=√4949x=Câu trả lời: a) x=−35−35x=3535x=3434−34−34x=3535x=3535:x=0,5-3535:x=3535:1212)=2323(x-3434-11212)=−1112−1112+−1712−1712e) 215215:(-21313-5x=1313-119119x=11451145g) x2+5959x2=1919x2=√4949x=

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