x-(50x/100+25x/200)=45/4
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
\(x-\left(\dfrac{50x}{100}+\dfrac{25x}{100}\right)=11\dfrac{1}{4}\)
\(x-\dfrac{3x}{4}=\dfrac{45}{4}\)
\(\dfrac{x}{4}=\dfrac{45}{4}\Rightarrow x=45\)
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
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
\(b,\dfrac{1}{5}:x=\dfrac{1}{5}-\dfrac{1}{7}\)
\(\dfrac{1}{5}:x=\dfrac{7}{35}-\dfrac{5}{35}\)
\(\dfrac{1}{5}:x=\dfrac{2}{35}\)
\(x=\dfrac{1}{5}:\dfrac{2}{35}\)
\(x=\dfrac{1}{5}.\dfrac{35}{2}\)
\(x=\dfrac{7}{2}\)
\(a)\frac{1}{5\cdot8}+\frac{1}{8\cdot11}+\frac{1}{11\cdot14}+...+\frac{1}{x(x+3)}=\frac{101}{1540}\)
\(\Rightarrow\frac{1}{3}\left[(\frac{1}{5}-\frac{1}{8})+(\frac{1}{8}-\frac{1}{11}+...+\frac{1}{x}-\frac{1}{x+3})\right]=\frac{101}{1540}\)
\(\Rightarrow\frac{1}{3}\left[\frac{1}{5}-\frac{1}{x+3}\right]=\frac{101}{1540}\)
\(\Rightarrow\frac{1}{5}-\frac{1}{x+3}=\frac{101}{1540}:\frac{1}{3}\)
\(\Rightarrow\frac{1}{5}-\frac{1}{x+3}=\frac{303}{1540}\)
\(\Rightarrow\frac{1}{x+3}=\frac{1}{5}-\frac{303}{1540}=\frac{5}{1540}=\frac{1}{308}\)
\(\Rightarrow x+3=308\Rightarrow x=305\)
\(b)x-(\frac{50x}{100}-\frac{25x}{200})=\frac{45}{4}\)
\(\Rightarrow x-(\frac{100x}{200}-\frac{25x}{200})=\frac{45}{4}\)
\(\Rightarrow x-\frac{5x}{8}=\frac{45}{4}\)
\(\Rightarrow\frac{3x}{8}=\frac{45}{4}\)
\(\Rightarrow3x=\frac{45}{4}\cdot8\)
\(\Rightarrow3x=90\Rightarrow x=30\)
\(c)1+2+3+4+...+x=820\)
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
\(x-\left(\frac{50x}{100}+\frac{25x}{100}\right)=\frac{45}{4}\)
\(x-\left(\frac{50x+25x}{100}\right)=\frac{45}{4}\)
\(x-\frac{75x}{100}=\frac{45}{4}\)
\(x-x\times\frac{3}{4}=\frac{45}{4}\)
\(x\times\left(1-\frac{3}{4}\right)=\frac{45}{4}\)
\(x\times\frac{1}{4}=\frac{45}{4}\)
\(x=\frac{45}{4}\div\frac{1}{4}\)
\(x=45\)
\(x-\left(\frac{50x}{100}+\frac{25x}{200}\right)=\frac{45}{4}\)
\(x-\left(\frac{100x}{200}+\frac{25x}{200}\right)=\frac{45}{4}\)
\(x-\left(\frac{100x+25x}{200}\right)=\frac{45}{4}\)
\(x-\frac{125x}{200}=\frac{45}{4}\)
\(x-x\frac{5}{8}=\frac{45}{4}\)
\(x\left(1-\frac{5}{8}\right)=\frac{45}{4}\)
\(x.\frac{3}{8}=\frac{45}{4}\)
\(x\)=\(\frac{45}{4}:\frac{3}{8}\)
\(x\)=\(30\)
ko biết
Cố đợi sang năm nhe