\(x-\left(\dfrac{50x}{100}+\dfrac{25x}{100}\right)=11\dfrac{1}{4}\)

\(x-\dfrac{3x}{4}=\dfrac{45}{4}\)

\(\dfrac{x}{4}=\dfrac{45}{4}\Rightarrow x=45\)

Ta có: \(x-\left(\dfrac{50x}{100}+\dfrac{25x}{200}\right)=11\dfrac{1}{4}\)

\(\Leftrightarrow x-\dfrac{1}{2}x-\dfrac{1}{8}x=\dfrac{45}{4}\)

\(\Leftrightarrow x\cdot\dfrac{3}{8}=\dfrac{45}{4}\)

hay x=30

giải lun nha

x-(4x/8+1x/8)=45/4

x-5x/8=45/4

-4x=45/4.8

-4x=90

x=90/(-4)

x=22,5

nếu đúng thì cho mk **** nha mk đang cần

22,5 nhé

22,5 nha bn

a) \(2^{x+2}-2^2=96\)

 <=> \(2^x.2^2-2^x=96\)

 <=> \(2^x\left(4-1\right)=96\)

<=> \(3.2^x=96\)

<=> \(2^x=32\)

<=> \(2^x=2^5\)

<=> x = 5 

b, \(x-\left(\frac{50x}{100}+\frac{25x}{200}\right)=11\frac{1}{4}\)

\(\Rightarrow x-\left(\frac{1x}{2}+\frac{1x}{8}\right)=\frac{45}{4}\)

\(\Rightarrow x-\left(\frac{4x}{8}+\frac{1x}{8}\right)=\frac{45}{4}\)

\(\Rightarrow x-\frac{5x}{8}=\frac{45}{4}\)

\(\Rightarrow\frac{8x}{8}-\frac{5x}{8}=\frac{45}{4}\)

\(\Rightarrow\frac{3x}{8}=\frac{45}{4}\Rightarrow x=\frac{45}{4}\div\frac{3}{8}=30\)

Vậy x = 30 

a)x=30

b)x=65

a) x-\(\left(\frac{50x}{100}+\frac{25x}{200}\right)\)=\(11\frac{1}{4}\)

<=>x - \(\frac{1}{2}x-\frac{1}{8}x\)=\(\frac{11.4+1}{4}\)

<=>\(\frac{3}{8}x=\frac{45}{4}\)

<=>x=\(\frac{45}{4}:\frac{3}{8}\)

<=>x=30

Vậy x=30

c) (x-5).\(\frac{30}{100}\)=\(\frac{20x}{100}+5\)

<=>(x-5).\(\frac{3}{10}\)=\(\frac{x}{5}\)+5

<=>\(\frac{3x}{10}-\frac{15}{10}=\frac{x}{5}+5\)

<=>\(\frac{3x}{10}-\frac{x}{5}=5+\frac{15}{10}\)

<=>\(\frac{x}{10}=\frac{13}{2}\)

<=>x=\(\frac{13.10}{2}\)

<=>x=65

Vậy: x=65

\(b,\dfrac{1}{5}:x=\dfrac{1}{5}-\dfrac{1}{7}\)

\(\dfrac{1}{5}:x=\dfrac{7}{35}-\dfrac{5}{35}\)

\(\dfrac{1}{5}:x=\dfrac{2}{35}\)

\(x=\dfrac{1}{5}:\dfrac{2}{35}\)

\(x=\dfrac{1}{5}.\dfrac{35}{2}\)

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

\(a)\frac{1}{5\cdot8}+\frac{1}{8\cdot11}+\frac{1}{11\cdot14}+...+\frac{1}{x(x+3)}=\frac{101}{1540}\)

\(\Rightarrow\frac{1}{3}\left[(\frac{1}{5}-\frac{1}{8})+(\frac{1}{8}-\frac{1}{11}+...+\frac{1}{x}-\frac{1}{x+3})\right]=\frac{101}{1540}\)

\(\Rightarrow\frac{1}{3}\left[\frac{1}{5}-\frac{1}{x+3}\right]=\frac{101}{1540}\)

\(\Rightarrow\frac{1}{5}-\frac{1}{x+3}=\frac{101}{1540}:\frac{1}{3}\)

\(\Rightarrow\frac{1}{5}-\frac{1}{x+3}=\frac{303}{1540}\)

\(\Rightarrow\frac{1}{x+3}=\frac{1}{5}-\frac{303}{1540}=\frac{5}{1540}=\frac{1}{308}\)

\(\Rightarrow x+3=308\Rightarrow x=305\)

\(b)x-(\frac{50x}{100}-\frac{25x}{200})=\frac{45}{4}\)

\(\Rightarrow x-(\frac{100x}{200}-\frac{25x}{200})=\frac{45}{4}\)

\(\Rightarrow x-\frac{5x}{8}=\frac{45}{4}\)

\(\Rightarrow\frac{3x}{8}=\frac{45}{4}\)

\(\Rightarrow3x=\frac{45}{4}\cdot8\)

\(\Rightarrow3x=90\Rightarrow x=30\)

\(c)1+2+3+4+...+x=820\)

Ta có : \(1+2+3+4+...+x=\frac{(1+x)\cdot x}{2}\)

Do đó : \(\frac{(1+x)\cdot x}{2}=820\)

\(\Rightarrow(1+x)\cdot x=820\cdot2\)

\(\Rightarrow(1+x)\cdot x=1640\)

\(\Rightarrow(1+x)\cdot x=40\cdot41\)

Vì x và x + 1 là hai số tự nhiên liên tiếp nên => x = 40

Chúc bạn học tốt :3

tui o bít nhưng ai kb vs tui o

 \(x-\left(\frac{50x}{100}+\frac{25x}{100}\right)=\frac{45}{4}\)

      \(x-\left(\frac{50x+25x}{100}\right)=\frac{45}{4}\)

                    \(x-\frac{75x}{100}=\frac{45}{4}\)

               \(x-x\times\frac{3}{4}=\frac{45}{4}\)

         \(x\times\left(1-\frac{3}{4}\right)=\frac{45}{4}\)

                       \(x\times\frac{1}{4}=\frac{45}{4}\)

                                 \(x=\frac{45}{4}\div\frac{1}{4}\)

                                 \(x=45\)

\(x-\left(\frac{50x}{100}+\frac{25x}{200}\right)=\frac{45}{4}\)

\(x-\left(\frac{100x}{200}+\frac{25x}{200}\right)=\frac{45}{4}\)

\(x-\left(\frac{100x+25x}{200}\right)=\frac{45}{4}\)

\(x-\frac{125x}{200}=\frac{45}{4}\)

\(x-x\frac{5}{8}=\frac{45}{4}\)

\(x\left(1-\frac{5}{8}\right)=\frac{45}{4}\)

\(x.\frac{3}{8}=\frac{45}{4}\)

\(x\)=\(\frac{45}{4}:\frac{3}{8}\)

\(x\)=\(30\)