1) \(\frac{2}{5}x\frac{1}{3}-\frac{2}{15}:\frac{1}{5}+\frac{3}{5}x\frac{1}{3}\)
2)\(\left(3\frac{1}{3}+2,5\right):\left(3\frac{1}{6}-4\frac{1}{5}\right)-\frac{11}{31}\)
3)\(\left[6+\left(\frac{1}{2}\right)^3-\left|-\frac{1}{2}\right|\right]:\frac{3}{12}\)
4)\(\frac{18}{37}+\frac{8}{24}+\frac{19}{37}-1\frac{23}{24}+\frac{2}{3}\)
5)\(\left(-2\right)^3x\left(\frac{3}{4}-0,25\right):\left(2\frac{1}{4}-1\frac{1}{6}\right)\)
6)\(\left(\frac{2}{5}\right)^2+5\frac{1}{2}x\left(45-2\right)+\frac{23}{4}\)
7)\(\frac{4}{9}-19\frac{1}{3}-\frac{4}{9}x39\frac{1}{3}\)
8)\(\left(-\frac{1}{2}\right)^2:\frac{1}{4}-2x\left(-\frac{1}{2}\right)^2\)
9)\(125\%x\left(-\frac{1}{2}\right)^3:\left(1\frac{5}{16}-1,5\right)+2008^0\)
giúp mình nha mai mình học rùi
Tính:
1,\(\frac{2}{5}+\left(-\frac{4}{5}\right)+\left(-\frac{1}{2}\right)\)
2,\(A=\frac{0,375-0,3+\frac{3}{11}+\frac{3}{12}}{-0,625+0,5-\frac{5}{11}-\frac{5}{12}}+\frac{1,5+1-0,75}{2,5+\frac{5}{3}-1,25}\)
3,\(B=\frac{\frac{1}{3}-\frac{1}{7}-\frac{1}{13}}{\frac{2}{3}-\frac{2}{7}-\frac{2}{13}}.\frac{\frac{1}{3}-0,25+0,2}{1\frac{1}{6}-0,875+0,7}+\frac{6}{7}\)
a,\(x:4\frac{1}{3}=2,5\)
b,\(\frac{1}{2}x-\frac{2}{3}x=\frac{7}{12}\)
c,\(\left(\frac{3}{7}x+1\right):\left(-4\right)=-\frac{1}{28}\)
d,\(\frac{2}{3}+\frac{1}{3}.\left(2x-1\right)=-5\)
\(1,5+1\frac{1}{4}\times x=\frac{2}{3}\)
Tìm x:\(\left(2,7.x-1\frac{1}{2}.x\right)\div\frac{2}{7}=\frac{-21}{4}\)
\(3\frac{1}{3}\times x+16\frac{3}{4}=-13,25\)
\(\left(4,5-2\times x\right)\div\frac{3}{4}=1\frac{1}{3}\)
\(\frac{1-0,5.\left(3,84-2,4\right):0,8}{\frac{4}{5}-\left(1\frac{1}{3}-2\frac{1}{6}\right)-1,5}\)
1, Tính \(\frac{1}{2}-\left(\frac{1}{3}+\frac{2}{3}\right)+\left(\frac{1}{4}+\frac{2}{4}+\frac{3}{4}\right)-\left(\frac{1}{5}+\frac{2}{5}+\frac{3}{5}+\frac{4}{5}\right)+...+\left(\frac{1}{100}+\frac{2}{100}+\frac{3}{100}+...+\frac{99}{100}\right)\)2,Tính \(\left(1-\frac{1}{2^2}\right)x\left(1-\frac{1}{3^2}\right)x\left(1-\frac{1}{4^2}\right)x...x\left(1-\frac{1}{n^2}\right)\)
Bài 1 tìm x;y \(\in\)Z (6 điểm)
a) (2x+1)(y+2)= 7
b) x+y+xy=5
c) x+6=y(x-1)
d)2xy+x+y=7
e) x2+y4=228
f)35x+64y=9672
Bài 2 tìm n \(\in\)N* (1,5 điểm)
n+9\(⋮\)n+3
6n+6\(⋮\)2n-4
3n2+2n+n\(⋮\)n+1
Bài 3 (2,5 điểm)
\(CMR:A=\left(\frac{1}{1}+\frac{1}{2}+\frac{1}{3}+...+\frac{1}{98}\right).2.3.4.5.6...98⋮99\)
\(CMR:1+\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{n}>1000\left(\forall n\right)\)
\(CMR:E=\frac{1.98+2.97+...+98.1}{1.2+2.3+3.4+...+98.99}=\frac{1}{2}\)
Giải chi tiết ai được trên 9 điểm mà nhanh nhất tớ tick cho
nhầm bài 2 (2,5 điểm) bài 3 (1,5 diểm)
Tính một cách hợp lí :
\(4\frac{3}{4}+\left(0,37\right)+\frac{1}{8}+\left(-1,28\right)+\left(-2,5\right)+3\frac{1}{2}\)
\(\frac{\frac{5}{22}+\frac{3}{13}-\frac{1}{2}}{\frac{4}{13}-\frac{2}{11}+\frac{3}{2}}\)
\(8\frac{2}{7}-\left(1\frac{1}{6}+25\%\right)\)
\(4\frac{3}{4}+\left(-0,37\right)+\left(-1,28\right)+\left(-2,5\right)+3\frac{1}{12}\)
(giải giúp mình với)