\(\frac{x}{7}=\frac{5x}{35}=\frac{x+16}{35}\)=> 5x = x + 16 => 4x = 16 => x = 16 : 4 = 4

\(a.\frac{x}{7}=\frac{x+16}{35}\)

\(\Rightarrow35x=7\left(x+16\right)\)

\(\Rightarrow35x=7x+112\)

\(\Rightarrow35x-7x=112\)

\(\Rightarrow28x=112\)

\(\Rightarrow x=112:28\)

\(\Rightarrow x=4\)

\(b.\frac{2-x}{16}=\frac{-4}{x-2}\)

\(\Rightarrow\frac{-\left(x-2\right)}{16}=\frac{-4}{x-2}\)

\(\Rightarrow\frac{x-2}{16}=\frac{4}{x-2}\)

\(\Rightarrow\left(x-2\right)^2=4.16\)

\(\Rightarrow\left(x-2\right)^2=64\)

\(\Rightarrow\left(x-2\right)^2=\left(\pm8\right)^2\)

\(\Rightarrow x-2=8\) hoặc \(x-2=-8\)

+) Nếu \(x-2=8\)

\(\Rightarrow x=8+2\)

\(\Rightarrow x=10\)

+) Nếu \(x-2=-8\)

\(\Rightarrow x=-8+2\)

\(\Rightarrow x=-6\)

Vậy \(x=10;x=-6\)

a) \(\frac{x}{7}=\frac{x+16}{35}\)

\(\Rightarrow35.x=7.\left(x+16\right)\)

\(\Rightarrow35.x=7.x+7.16\)

\(\Rightarrow35x=7x+112\)

\(\Rightarrow35x-7x=112\)

\(\Rightarrow28x=112\)

\(\Rightarrow x=4\)

Vậy .............

a) \(\frac{x}{7}=\frac{x+16}{35}\)

\(\Rightarrow\) x.35 = 7.(x + 16)

x.35 = 7x + 7.16

x.35 = 7x + 112

x.35 - 7x = 112

x.(35 - 7) = 112

x.28 = 112

x = 112 : 28

x = 4

b), c) tương tự

a) Ta có: \(\frac{x}{5}=\frac{x+6}{15}\Rightarrow15x=5\left(x+6\right)\)

                                         \(\Rightarrow15x=5x+30\)

                                         \(\Rightarrow10x=30\)

                                          => x        = 3

Vậy x = 3

b) \(\frac{x+10}{27}=\frac{x}{9}\Rightarrow9\left(x+10\right)=27x\)

                                \(\Rightarrow9x+90=27x\)

                                 \(\Rightarrow18x=90\)

                                  => x      = 5

Vậy x = 5

c) \(\frac{x+16}{35}=\frac{x}{7}\Rightarrow7\left(x+16\right)=35x\)

                                   \(\Rightarrow7x+112=35x\)

                                    \(\Rightarrow28x=112\)

                                    =>x = 4

Vậy x = 4

NĂM MỚI AN LÀNH

ai làm nhanh mk sẽ cho và tặng quà nha nhớ để lại địa chỉ qua tết mk sẽ gửi

cho 1 h nha

\(\frac{x}{7}=\frac{x+16}{35}\Leftrightarrow35x=7\left(x+16\right)\)

\(\Leftrightarrow35x-7x=112\)

\(\Leftrightarrow28x=112\Leftrightarrow x=4\)

\(\left(x-2\right)^2=25\Leftrightarrow x-2=5\)

\(\Leftrightarrow x=7\)

Thanh you bạn lê thị thu huyền

không có gì đâu^^

Ta có : \(\frac{x}{7}\)=\(\frac{x+16}{35}\)<=> 35x=7(x+16)

                                             <=>35x=7x+112

                                            <=>35x-7x=112

                                            <=>28x      =112

                                            <=>     x     = 4

a) \(\frac{3\left(2x+1\right)}{4}-\frac{5x+3}{6}+\frac{x+1}{3}=x+\frac{7}{12}\)

\(\frac{3.3\left(2x+1\right)}{12}-\frac{2\left(5x+3\right)}{12}+\frac{4\left(x+1\right)}{12}=\frac{12x+7}{12}\)

\(18x+9-10x-6+4x+4=12x+7\)

\(0x=0\) ( vô số nghiệm )

Vậy x \(\in\)R

b) ĐKXĐ :  x \(\ne\)-1;-3;-5;-7

\(\frac{1}{x^2+4x+3}+\frac{1}{x^2+8x+15}+\frac{1}{x^2+12x+35}=\frac{3}{16}\)

\(\frac{1}{\left(x+1\right)\left(x+3\right)}+\frac{1}{\left(x+3\right)\left(x+5\right)}+\frac{1}{\left(x+5\right)\left(x+7\right)}=\frac{3}{16}\)

\(\frac{1}{2}\left(\frac{1}{x+1}-\frac{1}{x+3}+\frac{1}{x+3}-\frac{1}{x+5}+\frac{1}{x+5}-\frac{1}{x+7}\right)=\frac{3}{16}\)

\(\frac{1}{x+1}-\frac{1}{x+7}=\frac{3}{8}\)

\(\left(x+1\right)\left(x+7\right)=16\)

Ta thấy x+1 và x+7 là 2 số cách nhau 6 đơn vị . Mà x + 1 < x + 7

\(\Rightarrow\)\(\hept{\begin{cases}x+1=2\\x+7=8\end{cases}\Rightarrow x=1}\)

hoặc \(\hept{\begin{cases}x+1=-2\\x+7=-8\end{cases}}\Rightarrow\hept{\begin{cases}x=-3\\x=-15\end{cases}}\)( loại )

Vậy x = 1

\(=\frac{16}{5}.\frac{15}{16}-\left(\frac{3}{4}+\frac{2}{7}\right):\left(\frac{-29}{28}\right)\)

\(=3-\left(\frac{21}{28}+\frac{8}{28}\right):\left(\frac{-29}{28}\right)\)

\(=3-\left(\frac{29}{28}\right).\left(\frac{-28}{29}\right)\)

\(=3-\left(-1\right)\)

\(=4\)

b)   \(=\left(\frac{1}{4}+\frac{25}{2}-\frac{5}{16}\right):\left(12-\frac{7}{12}:\left(\frac{3}{8}-\frac{1}{12}\right)\right)\)

       \(=\left(\frac{4}{16}+\frac{200}{16}-\frac{5}{16}\right):\left(12-\frac{7}{12}:\left(\frac{3.3}{2.3.4}-\frac{2}{2.3.4}\right)\right)\)

     \(=\left(\frac{199}{16}\right):\left(12-\frac{7}{12}:\left(\frac{9}{24}-\frac{2}{24}\right)\right)\)

      \(=\frac{199}{16}:\left(12-\frac{7}{12}.\frac{24}{7}\right)\)

    \(=\frac{199}{16}:\left(12-2\right)\)

\(=\frac{199}{16}:10\)

\(=\frac{199}{160}\)

c)   \(\left(\frac{-3}{5}+\frac{5}{11}\right):\frac{-3}{7}+\left(\frac{-2}{5}+\frac{6}{5}\right):\frac{-3}{7}\)

\(\left(\frac{-33}{55}+\frac{25}{55}\right):\frac{-3}{7}+\left(\frac{4}{5}\right):\frac{-3}{7}\)

\(\left(\frac{-8}{55}\right).\frac{-7}{3}+\frac{4}{5}.\frac{-7}{3}\)

\(\frac{-7}{3}\left(\frac{-8}{55}+\frac{4}{5}\right)\)

\(\frac{-7}{3}.\frac{36}{55}=\frac{-84}{55}\)

giờ mk phải đi ngủ r mai mk làm cho 

nhớ làm giúp mình nhá mai mình phải đi học r :<

x=4 nhé