Lời giải:
$(0,3-x).2\frac{1}{4}=\frac{-2}{5}$
$(0,3-x).\frac{9}{4}=\frac{-2}{5}$
$0,3-x=\frac{-2}{5}: \frac{9}{4}=\frac{-8}{45}$
$x=0,3-\frac{-8}{45}=\frac{43}{90}$
Tính tổng sau:
a) \(\dfrac{1}{9}+3,25+5\dfrac{3}{16}+4\dfrac{1}{3}+2,8+0,5\)
b) \(2\dfrac{1}{3}+0,45+4,25+\dfrac{1}{81}+6\dfrac{8}{27}\)
c) \(1,25+2\dfrac{1}{4}+4\dfrac{2}{5}+0,3+2,14+4\dfrac{1}{8}\)
Tìm \(x\)
1. \(\dfrac{1}{7}=\dfrac{8}{-x}\)
2. \(\dfrac{3x}{9}=\dfrac{2}{6}\)
3. \(4\dfrac{2}{5}:\left(\dfrac{-33}{10}\right)+x=-1\dfrac{5}{6}\)
4. \(45\%.x-2\dfrac{3}{8}=-1\dfrac{31}{40}\)
5. \(\left(x-2\dfrac{1}{4}\right):\left(-\dfrac{5}{6}\right)=3\)
1. Tìm x, biết:
a, \(1\dfrac{3}{5}\) + \(\dfrac{\dfrac{2}{7}+\dfrac{2}{17}+\dfrac{2}{37}}{\dfrac{5}{7}+\dfrac{5}{17}+\dfrac{5}{37}}\) . x = \(\dfrac{16}{5}\)
b, (\(\dfrac{1}{24.25}\) + \(\dfrac{1}{25.26}\) + . . . + \(\dfrac{1}{39.40}\) ) . 120 + x. \(\dfrac{1}{3}\) = -4
c, \(\left|x-\dfrac{1}{3}\right|\) . 2 + \(\dfrac{4}{5}\) = 0,24
d, \(\dfrac{24}{7x-3}\) = \(\dfrac{-4}{25}\)
e, ( 50% x + \(5\dfrac{1}{4}\) ) , \(\dfrac{-2}{3}\) = \(2\dfrac{5}{6}\)
f, \(1\dfrac{1}{3}\) - 25%\(\dfrac{-5}{12}\) + 2x = 1,6 : \(\dfrac{3}{5}\)
\(x-\dfrac{1}{5}=\dfrac{3}{4}\)
\(\dfrac{2}{5}x+\dfrac{1}{4}=\dfrac{1}{8}\)
tìm x,y thuộc z
a. \(\dfrac{-1}{4}:\dfrac{-3}{4}+\dfrac{1}{2}< x< \dfrac{7}{8}-\dfrac{1}{2}:\dfrac{-5}{6}\)
1: \(\dfrac{2\cdot\left(x+2\right)}{3}-\dfrac{5\cdot\left(x-1\right)}{4}=\dfrac{3\cdot\left(5-x\right)}{2}-1\dfrac{1}{2}\cdot\left(2x+3\right)\)
\(-4\dfrac{2}{5}\) : (\(\dfrac{-33}{10}\)) - x = \(-1\dfrac{5}{6}\)
tìm x biết
a) \(\dfrac{2}{3}\): x - \(\dfrac{5}{6}\)= 1\(\dfrac{1}{2}\)
b) (\(\dfrac{5}{6}\) . x + \(\dfrac{2}{3}\)) : (\(\dfrac{2}{5}\) +\(1\dfrac{1}{3}\) )\(\dfrac{4}{9}\)
c) \(|\)x - \(\dfrac{4}{3}\)\(|\) - \(\dfrac{5}{6}\) = \(\dfrac{3}{5}\) . \(1\dfrac{1}{2}\)
d) \(|\)2x + \(\dfrac{1}{2}\)\(|\) - \(\dfrac{3}{4}\)=\(3\dfrac{1}{2}\)
e) \(|\dfrac{3}{2}\)x - \(\dfrac{5}{6}|\)+ \(\dfrac{12}{5}\)= \(1\dfrac{1}{2}\)
tìm x biết :
1.\(\dfrac{-5}{6}+\dfrac{8}{3}+\dfrac{-29}{6}\le x\le\dfrac{-1}{2}+2+\dfrac{5}{2}\)
2.\(\left(2,7x-1\dfrac{1}{2}x\right):\dfrac{2}{7}=\dfrac{-21}{4}\)
3.\(\left|2x-\dfrac{3}{4}\right|=1\)
làm hộ mik 3 con này cái
