tìm x biết rằng :
a) x - \(\left(\frac{50x}{100}+\frac{25x}{200}\right)=11\frac{1}{4}\) c) ( x - 5 ) . \(\frac{30}{100}=\frac{20x}{100}+5\)
Tìm x:
a) \(x-\left(\frac{50x}{160}+\frac{25x}{200}\right)=11\frac{1}{4}\)
b)\(\left(x-5\right)\cdot\frac{30}{100}=\frac{200x}{100}+5\)
Giúp mình nhanh với, cảm ơn các bạn rất nhiều!
Tìm x, biết:
a, \(x-\left(\frac{50x}{100}+\frac{25x}{200}\right)=11\frac{1}{4}\) b,\(\left(x-5\right).\frac{30}{100}=\frac{200x}{100}+5\)
c,\(\frac{x+1}{2}=\frac{8}{x+1}\) d, \(x:\left(9\frac{1}{2}-\frac{3}{2}\right)=\frac{0,4+\frac{2}{9}-\frac{2}{11}}{1,6+\frac{8}{9}-\frac{8}{11}}\)
\(c,\frac{x+1}{2}=\frac{8}{x+1}\)
\(\Rightarrow(x+1)(x+1)=2.8\)
\(\Rightarrow(x+1)^2=16\)
\(\Rightarrow(x+1)^2=4^2\)
\(\Rightarrow x+1=4\)
\(\Rightarrow x=4-1\)
\(\Rightarrow x=3\)
\(a,x-(\frac{50x}{100}+\frac{25x}{200})=11\frac{1}{4}\)
\(\Rightarrow x-\frac{50x+25x}{100}=\frac{45}{4}\)
\(\Rightarrow\frac{100x}{100}-\frac{75x}{100}=\frac{45}{4}\)
\(\Rightarrow\frac{100x-75x}{100}=\frac{1125}{100}\)
\(\Rightarrow25x=1125\)
\(\Rightarrow x=45\)
\(b,(x-5)\frac{30}{100}=\frac{200x}{100}+5\)
\(\Rightarrow\frac{30x}{100}-\frac{3}{2}=\frac{200x}{100}+5\)
\(\Rightarrow\frac{30x}{100}-\frac{200x}{100}=5+\frac{3}{2}\)
\(\Rightarrow\frac{-170x}{100}=\frac{13}{2}\)
\(\Rightarrow\frac{-170x}{100}=\frac{650}{100}\)
\(\Rightarrow-170x=650\)
\(\Rightarrow x=\frac{-65}{17}\)
TÌM X:
\(x-\left(\frac{50x}{100}+\frac{25x}{100}\right)=11\frac{1}{4}\)
\(x-\left(\frac{50x}{100}+\frac{25x}{100}\right)=\frac{45}{4}\)
\(x-\left(\frac{50x+25x}{100}\right)=\frac{45}{4}\)
\(x-\frac{75x}{100}=\frac{45}{4}\)
\(x-x\times\frac{3}{4}=\frac{45}{4}\)
\(x\times\left(1-\frac{3}{4}\right)=\frac{45}{4}\)
\(x\times\frac{1}{4}=\frac{45}{4}\)
\(x=\frac{45}{4}\div\frac{1}{4}\)
\(x=45\)
\(x-\left(\frac{50x}{100}+\frac{25x}{200}\right)=\frac{45}{4}\)
\(x-\left(\frac{100x}{200}+\frac{25x}{200}\right)=\frac{45}{4}\)
\(x-\left(\frac{100x+25x}{200}\right)=\frac{45}{4}\)
\(x-\frac{125x}{200}=\frac{45}{4}\)
\(x-x\frac{5}{8}=\frac{45}{4}\)
\(x\left(1-\frac{5}{8}\right)=\frac{45}{4}\)
\(x.\frac{3}{8}=\frac{45}{4}\)
\(x\)=\(\frac{45}{4}:\frac{3}{8}\)
\(x\)=\(30\)
Tìm x:
a) x - (\(\frac{50x}{100}+\frac{25x}{200}\)) = \(11\frac{1}{4}\)
b) (x - 5) . \(\frac{30}{100}\) = \(\frac{200x}{100}\) + 5
Tìm x:
a) x - (\(\frac{50x}{100}\) + \(\frac{25x}{100}\)) = \(11\frac{1}{4}\)
b) (x-5) . \(\frac{30}{100}\) = \(\frac{200x}{100}\) + 5
- Help me!.
\(\text{Tìm x , biết : }\)
\(a.\frac{1}{5.8}+\frac{1}{8.11}+\frac{1}{11.14}+...+\frac{1}{x\left(x+3\right)}=\frac{101}{1540}\)
\(b.x-\left(\frac{50x}{100}+\frac{25x}{200}\right)=\frac{45}{4}\)
\(c.1+2+3+4+...+x=820\)
Ai làm nhanh mk cho 20 tích
\(a)\frac{1}{5\cdot8}+\frac{1}{8\cdot11}+\frac{1}{11\cdot14}+...+\frac{1}{x(x+3)}=\frac{101}{1540}\)
\(\Rightarrow\frac{1}{3}\left[(\frac{1}{5}-\frac{1}{8})+(\frac{1}{8}-\frac{1}{11}+...+\frac{1}{x}-\frac{1}{x+3})\right]=\frac{101}{1540}\)
\(\Rightarrow\frac{1}{3}\left[\frac{1}{5}-\frac{1}{x+3}\right]=\frac{101}{1540}\)
\(\Rightarrow\frac{1}{5}-\frac{1}{x+3}=\frac{101}{1540}:\frac{1}{3}\)
\(\Rightarrow\frac{1}{5}-\frac{1}{x+3}=\frac{303}{1540}\)
\(\Rightarrow\frac{1}{x+3}=\frac{1}{5}-\frac{303}{1540}=\frac{5}{1540}=\frac{1}{308}\)
\(\Rightarrow x+3=308\Rightarrow x=305\)
\(b)x-(\frac{50x}{100}-\frac{25x}{200})=\frac{45}{4}\)
\(\Rightarrow x-(\frac{100x}{200}-\frac{25x}{200})=\frac{45}{4}\)
\(\Rightarrow x-\frac{5x}{8}=\frac{45}{4}\)
\(\Rightarrow\frac{3x}{8}=\frac{45}{4}\)
\(\Rightarrow3x=\frac{45}{4}\cdot8\)
\(\Rightarrow3x=90\Rightarrow x=30\)
\(c)1+2+3+4+...+x=820\)
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
a) xy-3x-y=0
b)Làm sao cho \(\frac{10}{x+7}\)đạt tối giản
c) Cho \(A=\frac{-5x}{21}+\frac{-5y}{21}+\frac{-5z}{21}\) biết x+y=-z
d) Cho \(A=\frac{10^{2004}+1}{10^{2005}+1}\)và\(B=\frac{10^{2005}+1}{10^{2006}+1}\)So sánh A và B
e) \(x-\left(\frac{50x}{100}+\frac{25x}{200}\right)=11\frac{1}{4}\)
f)\(\left(x-5\right)\times\frac{30}{100}=\frac{200x}{100}+5\)
Cái này thực ra là lớp 6 mik ko chọn được Các bạn làm đầy đủ công thức và phép toán nha mình cần gấp
Tìm số tự nhiên x, biết: \(\left(x-5\right)\frac{30}{100}=\frac{20x}{100}+5\)
Ta có: \(\left(x-5\right)\frac{30}{100}=\frac{20x}{100}+5\)
\(\Rightarrow\left(x-5\right)\frac{3}{10}=\frac{x}{5}+5\)
\(\Rightarrow\frac{3x-15}{10}=\frac{25+x}{5}\)
\(\Rightarrow5\left(3x-15\right)=10\left(25+x\right)\)
\(\Rightarrow15x-75=250+10x\)
\(\Rightarrow15x-10x=250+75\)
\(\Rightarrow5x=325\Rightarrow x=\frac{325}{5}=65\)
\(\left(x-8\right).\frac{3}{10}=\frac{1}{5}x+5\)
\(\frac{3}{10}x-\frac{3}{2}=\frac{1}{5}x+5\)
\(\frac{3}{10}x=\frac{1}{5}x+6,5\)
\(\Rightarrow\frac{1}{10}x=6,5\)
\(x=\frac{6,5}{\frac{1}{10}}\)
\(x=65\)
Vậy \(x=65\)
Tìm số tự nhiên x biết: \(\left(x-5\right)\frac{30}{100}=\frac{20x}{100}+5\)