1:92/3-3/4)^2
Cho M =1/99+2/98+3/97+.........+99/1/1/2+1/3+1/4+.........+1/100 va N = 92-1/9-2/10-3/11-......-92/100/1/45+1/50+1/55+......+1/500. Tinhs M-2.N = ?
Q=1/2*3*4+1/3*4*5+1/4*5*6+........+1/90*91*92
[92--1/9-2/10-3/11-4/12-92/100] :[1/45+1/50+1/55+1/60+1/500]
1 tính nhanh :
a.5/27 + 3/4 + 22/27 + 1/4 b. 89/92 - 30 /92 - 59/92
2 .khối lớp 5 có 210 học sinh ,khối lớp 4 là 70 học sinh , biết số học sinh khối 5 bảng 4/3 khối 4 .tính sổ học sinh của 2 khối
\(\frac{5}{27}+\frac{3}{4}+\frac{22}{27}+\frac{1}{4}\)
\(=\left(\frac{5}{27}+\frac{22}{27}\right)+\left(\frac{3}{4}+\frac{1}{4}\right)\)
\(=1+1\)
\(=2\)
\(\frac{89}{92}-\frac{30}{92}-\frac{59}{92}\)
\(=\frac{89-30-59}{92}\)
\(=\frac{59-59}{92}\)
\(=\frac{0}{92}\)
\(=0\)
bài 2 đề sai rồi
bạn xem lại nhé
Tìm x
\(\dfrac{1}{4}x-\dfrac{1}{3}=\dfrac{-5}{9}\)
\(2^{x-3}-3.2^x=-92\)
1) \(\dfrac{1}{4}x-\dfrac{1}{3}=\dfrac{-5}{9}\)
\(\Rightarrow\dfrac{1}{4}x=-\dfrac{2}{9}\Rightarrow x=-\dfrac{8}{9}\)
2) \(2^{x-3}-3.2^x=-92\)
\(\Rightarrow2^x\left(2^{-3}-3\right)=-92\)
\(\Rightarrow2^x.\dfrac{-23}{9}=-92\)
\(\Rightarrow2^x=32\Rightarrow x=5\)
Tính A=92-1/9-2/10-3/11-4/12-5/3-...-91/99-92/100 / 1/45+1/50+1/55+...+1/495+1/500
bài 1: thực hiện phép tính
1) (13.17\(^4\)+4.17\(^4\)):17\(^3\)-(14.\(3^3\)-14.3\(^2\)):9
2) \(2^3\).\(5^2\)-[131-(23-2\(^3\))\(^2\)]
bài 2: tìm x
1) 6\(^2\).x+14.x-3\(^4\)=69
2) 3\(^x\)=81
3) 3. (2x+1)\(^2\)=75
2:
1: =>36x+14x=69+81=150
=>50x=150
=>x=3
2: 3^x=81
=>3^x=3^4
=>x=4
3: 3(2x+1)^2=75
=>(2x+1)^2=25
=>2x+1=5 hoặc 2x+1=-5
=>x=-3 hoặc x=2
1:
1: \(\dfrac{13\cdot17^4+4\cdot17^4}{17^3}-\dfrac{14\cdot3^3-14\cdot3^2}{9}\)
\(=\dfrac{17^4\cdot\left(13+4\right)}{17^3}-\dfrac{14\cdot3^2\left(3-1\right)}{9}\)
\(=17\cdot17-14\cdot2\)
=289-28
=261
2:
\(2^3\cdot5^2-\left[131-\left(23-2^3\right)^2\right]\)
\(=8\cdot25-131+\left(-1\right)^2\)
=69+1
=70
Giải phương trình sau:
1. x + 2/ 98 + x + 4/96 = x + 6/94 + x + 8/92
2. 1/2 (x + 1) + 1/4 (x +3) = 3 - 1/3 (x + 2)
1: \(\Leftrightarrow\left(\dfrac{x+2}{98}+1\right)+\left(\dfrac{x+4}{96}+1\right)=\left(\dfrac{x+6}{94}+1\right)+\left(\dfrac{x+8}{92}+1\right)\)
=>x+100=0
hay x=-100
2: \(\Leftrightarrow x\cdot\dfrac{1}{2}+\dfrac{1}{2}+\dfrac{1}{4}x+\dfrac{3}{4}=3-\dfrac{1}{3}x-\dfrac{2}{3}\)
=>3/4x+5/4=-1/3x+7/3
=>13/12x=13/12
hay x=1
tính H = \(\dfrac{\dfrac{1}{99}+\dfrac{2}{98}+\dfrac{3}{97}+...+\dfrac{98}{2}+\dfrac{99}{1}}{\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{4}+...+\dfrac{1}{100}}:\dfrac{92-\dfrac{1}{9}-\dfrac{2}{10}-\dfrac{3}{11}-...-\dfrac{92}{100}}{\dfrac{1}{45}+\dfrac{1}{50}+\dfrac{1}{55}+...+\dfrac{1}{500}}\)