Tham khảo:

Nguồn:Vietjack

I think that the best leisure activity for teenagers is playing sports. Firstly, they can find friends who have the same interests. Secondly, physical activities are a good way to relieve stress and reduce depression. Moreover, sports can help develop teamwork and leadership skills that may be very necessary for their future jobs. Their parents should give advice on choosing a suitable leisure activity; however, teenagers themselves will make the final decision

chụp ảnh được không

Phải đây ko

Ta có:

\(\frac{x-1}{2}=\frac{y-2}{3}=\frac{z-3}{4}=\frac{2x-2}{4}=\frac{3y-6}{9}\)

Áp dụng tính chất của dãy tỉ số = nhau ta có:

\(\frac{x-1}{2}=\frac{y-2}{3}=\frac{z-3}{4}=\frac{2x-2}{4}=\frac{3y-6}{9}=\frac{\left(2x-2\right)+\left(3y-6\right)-\left(z-3\right)}{4+9-4}\)

\(=\frac{\left(2x+3y-z\right)-5}{9}=\frac{50-5}{9}=\frac{45}{9}=5\)

\(\Rightarrow\begin{cases}x-1=2.5=10\\y-2=3.5=15\\z-3=4.5=20\end{cases}\)\(\Rightarrow\begin{cases}x=11\\y=17\\z=23\end{cases}\)

Vậy x = 11; y = 17; z = 23

1) \(x^2+\frac{8}{9}=\frac{41}{36}\)\(\Leftrightarrow x^2=\frac{1}{4}\Leftrightarrow x=\pm\frac{1}{2}\)

2) \(\left(x-3\right)^2+-\frac{9}{25}=\frac{2}{5}.\frac{8}{5}\)

\(\Leftrightarrow\left(x-3\right)^2=1\)

\(\Leftrightarrow\orbr{\begin{cases}x-3=1\\x-3=-1\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=4\\x=2\end{cases}}\)

3) \(\frac{3}{11}.\frac{22}{6}-\left(x-1\right)^2=\frac{7}{16}\)

\(\Leftrightarrow\left(x-1\right)^2=\frac{9}{16}\)

\(\Leftrightarrow\orbr{\begin{cases}x-1=\frac{3}{4}\\x-1=-\frac{3}{4}\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=\frac{7}{4}\\x=\frac{1}{4}\end{cases}}\)

4) \(1+\left(x+1\right)^3=\frac{37}{64}\)

\(\Leftrightarrow\left(x+1\right)^3=-\frac{27}{64}\)

\(\Rightarrow x+1=-\frac{3}{4}\)

\(\Leftrightarrow x=-\frac{7}{4}\)

5) \(\left(x-\frac{1}{2}\right)^2-\frac{9}{16}=1\)

\(\Leftrightarrow\left(x-\frac{1}{2}\right)^2=\frac{25}{16}\)

\(\Leftrightarrow\orbr{\begin{cases}x-\frac{1}{2}=\frac{5}{4}\\x-\frac{1}{2}=-\frac{5}{4}\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=\frac{7}{4}\\x=-\frac{3}{4}\end{cases}}\)

6) Bn ghi rõ đề nha mk ko hiểu 

6 ) \(\frac{3-x}{5-x}=\left(\frac{-3}{5}\right)^2\)

\(\frac{3-x}{5-x}=\frac{9}{25}\Leftrightarrow\frac{3-x}{5-x}-\frac{9}{25}\Leftrightarrow\frac{75-25x}{125-25x}-\frac{45-9x}{125-5x}=0\)

\(\Rightarrow\frac{75-25-45+9x}{125-25x}=0\Leftrightarrow5+9x=0\Leftrightarrow x=\frac{-5}{9}\)

Có ghi thiếu đề k v ?

cho mk hỏi: viết hỗn số tk nào vậy

chào bn mik đến từ năm 2022

\(\left(\dfrac{1}{2}+1\right)\times\left(\dfrac{1}{3}+1\right)\times\left(\dfrac{1}{4}+1\right)\times\left(\dfrac{1}{5}+1\right)\times\left(\dfrac{1}{6}+1\right)\)

\(=\dfrac{3}{2}\times\dfrac{4}{3}\times\dfrac{5}{4}\times\dfrac{6}{5}\times\dfrac{7}{6}\)

\(=\dfrac{3\times4\times5\times6\times7}{2\times3\times4\times5\times6}\)

\(=\dfrac{7}{2}\)

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Ta có: ( x - 2) x ( y + 3) = -13 = (-13) x 1 = (-1) x 13

* Nếu x - 2 = -13 => x = (-13) + 2 = -11

         y + 3 = 1 => y = 1-3 = -2 

* Nếu x-2 = -1 => x = (-1) + 2 = 1

         y + 3 = 13 => y = 13 - 3 = 10

Vậy có 2 cặp x;y x;y(-11;-2)

                          x;y(1;10)

a) 412 - ( 324 - x ) = 543

                324 - x   = 412 - 543

                324 - x   = -131

                         x   = 324 - (-131 )

                         x   = 455

a) 412-(324-x)=543

    324-x=412-543

    324-x=-131

          x=324+131

          x=455

b) 3.(x+41)=153

       x+41=51

       x=51-41=10

c) 276-5(x+2)=56

          5(x+2)=220

              x+2=44

                  x=44-2=42

d) 10+2x=4¹⁵:4¹²

    10+2x=4³

      10+2x=64

            2x=64-10=54

             x=54:2=27

e) 5x-206=2⁴.4

    5x-206=2⁴.2²

    5x-206=2⁶

   5x-206=64

         5x=270

          x=270:5=54