a: \(\Leftrightarrow\dfrac{x+1}{2x+1}=\dfrac{x+4}{2x+6}\)
=>(x+1)(2x+6)=(2x+1)(x+4)
\(\Leftrightarrow2x^2+6x+2x+6=2x^2+8x+x+4\)
=>9x+4=8x+6
=>x=2
b: \(x^2+5x=0\)
=>x(x+5)=0
=>x=0 hoặc x=-5
1. Tìm x:
a. |x| = 5,6 b. |x-3,5| = 5 c.|x+\(\dfrac{3}{4}\)| - \(\dfrac{1}{2}\)= 0 d. |4x| -|-13,5| = |\(\dfrac{9}{4}\)|
e. (x-1)3 = 27 f. (2x-3)2=36 g. 5x + 2= 625 h. (2x -1) 3 = -8
i.* \(\dfrac{1}{4}\).\(\dfrac{2}{6}.\dfrac{3}{8}.\dfrac{4}{10}.\dfrac{5}{12}...\dfrac{30}{62}.\dfrac{31}{64}=2^x\)
ĐỀ 2:
1. Tính:
A. \(\left(-\dfrac{2}{3}\right)^2+\left(-\dfrac{7}{8}\right)+\left(-\dfrac{11}{12}\right)\)
B. \(\left(\dfrac{-1}{3}\right)^2:\dfrac{1}{6}-2.\left(\dfrac{-1}{2}\right)^3\)\
C. \(\dfrac{-1}{5}-\left(\dfrac{1}{2}+\dfrac{3}{4}\right)^2:\dfrac{5}{8}\)
D. \(\left|\dfrac{-3}{2}+1,2\right|+1\dfrac{2}{3}:6\)
2. Tìm x, biết:
a. \(\dfrac{2}{3}x-\dfrac{1}{3}x=\dfrac{5}{12}\)
b. \(\left(x-\dfrac{12}{7}\right):1\dfrac{1}{5}=\dfrac{4}{7}\)
c. \(\dfrac{2}{5}+\left|x+1\right|=\dfrac{3}{4}\)
3. Tìm x, y biết:
a. \(\dfrac{x}{18}=\dfrac{y}{15}\)và x - y = -30
b. 7x = 9x và 10x - 8x = 68
c. \(\left(x-\dfrac{1}{2}\right)^{50}+\left(y+\dfrac{1}{3}\right)^{40}=0\)
* Lm nhanh nha
tim
\(\dfrac{31-2x}{x+23}=\dfrac{9}{4}\),a
b,\(\dfrac{\left|2x-1\right|}{\dfrac{1}{2}}=\dfrac{18}{5}\)
c, \(\dfrac{x-2}{x-1}=\dfrac{x+4}{x+7}\)
d, \(\dfrac{3x+2}{5x-3}=\dfrac{3x-1}{5x-3}\)
ĐỀ 1:
1. Tính:
a. \(\dfrac{7}{23}\left[\left(\dfrac{-8}{6}\right)-\dfrac{45}{18}\right]\)
b. \(\dfrac{1}{5}:\dfrac{1}{10}-\dfrac{1}{3}\left(\dfrac{6}{5}-\dfrac{9}{4}\right)\)
c. \(\dfrac{3}{5}.\left(\dfrac{-8}{3}\right)-\dfrac{3}{5}:\left(-6\right)\)
d. \(\dfrac{1}{2}\left(\dfrac{4}{3}+\dfrac{2}{5}\right)-\dfrac{3}{4}\left(\dfrac{8}{9}+\dfrac{16}{3}\right)\)
e. \(\dfrac{6}{7}:\left(\dfrac{3}{26}-\dfrac{3}{13}\right)+\dfrac{6}{7}\left(\dfrac{1}{10}-\dfrac{8}{5}\right)\)
2. Tìm x, biết:
a. \(1\dfrac{2}{5}x+\dfrac{3}{7}=\dfrac{4}{5}\)
b. |x - 1,5| = 2
c. \(\dfrac{4}{5}-\left|x-\dfrac{1}{6}\right|=\dfrac{2}{3}\)
d. 3x . 2x = 216
e. \(\dfrac{1}{2}\left(x-\dfrac{1}{3}\right)+\dfrac{-1}{2}=\dfrac{3}{4}\)
* Lm nhanh nha
Ths you <3
13 Tìm x, biết :
a) \(\dfrac{2}{3}x+4=-12\); b) \(\dfrac{3}{4}+\dfrac{1}{4}:x=-3\); c) \(\left|3x-5\right|=4\)
d) \(\dfrac{x+1}{10}+\dfrac{x+1}{11}+\dfrac{x+1}{12}=\dfrac{x+1}{13}+\dfrac{x+1}{14}\) ;
e) \(\dfrac{x+4}{2000}+\dfrac{x+3}{2001}=\dfrac{x+2}{2002}+\dfrac{x+1}{2003}\)
Tìm x biết:
a) \(\dfrac{x}{2}-\dfrac{1}{x}=\dfrac{1}{12}\)
b) 2x - 3 < 0
c) (2x-4) (9-3x) >0
d)\(\dfrac{2x}{3}-\dfrac{3}{4}\) > 0
e) (\(\dfrac{3}{4}\) - 2x)(\(\dfrac{-3}{5}+\dfrac{2}{-61}-\dfrac{17}{51}\)) nhỏ hơn hoặc bằng 0
f)( \(\dfrac{3}{2x}-4\)) . \(\dfrac{5}{3}\)
câu 1 tìm x biết
\((-1\dfrac{1}{5}+x)\div(-3\dfrac{3}{5})=\dfrac{-7}{4}+\dfrac{1}{4}\div\dfrac{1}{8}\)
\(\dfrac{5}{7}+\dfrac{2}{3}x=\dfrac{3}{10}\)
\(-\dfrac{22}{15}x+\dfrac{1}{3}=|-\dfrac{2}{3}+\dfrac{1}{5}|\)
Tinh x:
a)\(\dfrac{3}{4}+\dfrac{1}{4}:x=\dfrac{2}{5}\)
b)\(\dfrac{1}{4}+\dfrac{1}{3}:2x=-5\)
c)\(-2+\left|x+\dfrac{1}{5}\right|=\dfrac{9}{10}\)
Tìm số nguyên x biết:
a. \(-4\dfrac{3}{5}.2\dfrac{4}{23}\)<x<\(-2\dfrac{3}{5}:1\dfrac{6}{15}\) b. \(-4\dfrac{1}{3}.\left(\dfrac{1}{2}-\dfrac{1}{6}\right)< x< -\dfrac{2}{3}\left(\dfrac{1}{3}-\dfrac{1}{2}-\dfrac{3}{4}\right)\)
