1) \(x-\dfrac{1}{2}=\dfrac{1}{3}+\dfrac{-1}{4}\)
\(\Rightarrow x-\dfrac{1}{2}=\dfrac{1}{12}\)
\(\Rightarrow x=\dfrac{7}{12}\)
Vậy ...
2) \(x+\dfrac{1}{3}=\dfrac{1}{2}-\dfrac{1}{4}\)
\(\Rightarrow x+\dfrac{1}{3}=\dfrac{1}{4}\)
\(\Rightarrow x=\dfrac{-1}{12}\)
Vậy ...
BT2: Tìm x, biết
3) \(\dfrac{1}{2}.\left(x-\dfrac{1}{3}\right)=\dfrac{1}{3}.\left(x-\dfrac{1}{4}\right)\)
4) \(\text{ | }x-\dfrac{1}{3}\text{\text{ |}}-\dfrac{1}{3}=\dfrac{1}{3}\)
Bài 1. Tính giá trị biểu thức
125%.\((\dfrac{-1}{2})^2\):\((1\dfrac{5}{16}-1,5)+2008^0\)
\(\dfrac{2}{3.5}+\dfrac{2}{5.3}+\dfrac{2}{7.9}+\dfrac{2}{9.11}+\dfrac{2}{11.13}+\dfrac{2}{13.15}\)
Bài 2. Tìm x, biết
x:\(3\dfrac{1}{15}=1\dfrac{1}{12}\)
\(\dfrac{3}{4}.x=27\)
\(x.\dfrac{1}{4}=\dfrac{5}{8}.\dfrac{2}{3}\)
\(\left(x+\dfrac{1}{4}\right):\dfrac{3}{7}=\dfrac{1}{6}\)
\(\dfrac{3}{4}-2.|2x-\dfrac{2}{3}|=2\)
\(\dfrac{2}{3}x-\dfrac{1}{2}x=\dfrac{5}{2}\)
Tìm x, biết:
1. \(\left(\dfrac{2x}{5}+2\right):\left(-4\right)=-1\dfrac{1}{2}\)
2. x. ( x + 1) = 0
3. 2x - 16 = 40 + x
4. x : \(\dfrac{5}{3}\) + \(\dfrac{1}{3}\) = \(\dfrac{-2}{5}\)
5. 3\(\dfrac{1}{2}\) - \(\dfrac{1}{2}\) x = \(\dfrac{2}{3}\)
6. \(\dfrac{x}{4}=\dfrac{9}{x}\)
7. \(\dfrac{1}{3}+\dfrac{1}{2}:x=\) -0,25
BT3: Tìm x, biết:
7) \(\dfrac{-5}{17}+\dfrac{3}{17}\le\dfrac{x}{17}\le\dfrac{13}{17}+\dfrac{-11}{17}\)
8) \(\dfrac{2}{3}\left(\dfrac{1}{2}+\dfrac{3}{4}-\dfrac{1}{3}\right)\le\dfrac{x}{18}\le\dfrac{7}{3}\left(\dfrac{1}{2}-\dfrac{1}{6}\right)\)
Tìm số nguyên x , biết rằng
\(4\dfrac{1}{3}\)\(.\left(\dfrac{1}{6}-\dfrac{1}{2}\right)\)_< x _< \(\dfrac{2}{3}.\left(\dfrac{1}{3}-\dfrac{1}{2}-\dfrac{3}{4}\right)\)
BT2: Tìm x\(\in\) N*, biết
2) \(\dfrac{1}{2.3}+\dfrac{1}{3.4}+\dfrac{1}{4.5}+....+\dfrac{1}{x.\left(x+1\right)}=\dfrac{299}{600}\)
BT2: Tính nhanh
5) \(\dfrac{1}{7}.\dfrac{2}{5}+\dfrac{1}{7}.\dfrac{1}{5}+\dfrac{1}{7}.\dfrac{4}{5}\)
6) \(\dfrac{-3}{7}.\dfrac{19}{11}+\dfrac{-2}{7}.\dfrac{3}{11}+4\dfrac{6}{11}\)
BT2: Tính nhanh
3) \(\dfrac{2}{3}-\left(-\dfrac{1}{4}\right)+\dfrac{3}{5}-\dfrac{7}{45}-\left(-\dfrac{5}{9}\right)+\dfrac{1}{12}+\dfrac{1}{90}\)
4) B = \(\dfrac{1}{3}-\dfrac{3}{4}-\left(-\dfrac{3}{5}\right)+\dfrac{1}{64}-\dfrac{2}{9}-\dfrac{1}{36}+\dfrac{1}{15}\)
Giúp mk nhé các bạn!
Bài 1 : Tìm x
a) 4\(\dfrac{1}{2}\)x : \(\dfrac{5}{12}\)=0,5 b)1,5+1\(\dfrac{1}{4}\).x= \(\dfrac{2}{3}\) c) 7,5.1\(\dfrac{3}{4}\)=\(6\dfrac{2}{5}\) d)(x - 5):\(\dfrac{1}{3}\)=\(\dfrac{2}{5}\) e) (4,5-2x):\(\dfrac{3}{4}\)=1\(\dfrac{1}{3}\) f) (2,7x - 1\(\dfrac{1}{2}\)x) : \(\dfrac{2}{7}=\dfrac{-21}{7}\)
Bài 2 : tìm a,b biết
\(\dfrac{a}{27}=\dfrac{-5}{9}=\dfrac{-45}{b}\)
