8 nhan 5
tinh nhanh
1/10 nhan 2/9 nhan 3/8 nhan 4/7 nhan 5/6 nhan 6/5 nhan 7/4 nhan 8/3 nhan 9/ 2
1/10x(2/9x9/2)x(3/8x8/3)x(5/6x6/5)=1/10x1x1x1=1/10
tinh:D=3/5 nhan 8 + 11/8 nhan 19 + 12/19 nhan 31 + 70/31 nhan 101 + 99/101 nhan 200
Đề như thế nào vậy?
Nư thế này :\(D=\dfrac{3}{5.8}+\dfrac{11}{8.19}+\dfrac{12}{19.31}+\dfrac{70}{31.101}+\dfrac{99}{101.200}\)
Hay là \(D=\dfrac{3}{5}.8+\dfrac{11}{8}.19+\dfrac{12}{19}.31+\dfrac{70}{31}.101+\dfrac{99}{101}.200\)
Nếu là cách đầu thì mình làm thế này:
\(D=\dfrac{3}{5.8}+\dfrac{11}{8.19}+\dfrac{12}{19.31}+\dfrac{70}{31.101}+\dfrac{99}{101.200}\)
\(D=\dfrac{1}{5}-\dfrac{1}{8}+\dfrac{1}{8}-\dfrac{1}{19}+\dfrac{1}{19}-\dfrac{1}{31}+\dfrac{1}{31}-\dfrac{1}{101}+\dfrac{1}{101}-\dfrac{1}{200}\)
\(D=\dfrac{1}{5}-\dfrac{1}{200}\)
\(D=\dfrac{39}{200}\)
Vậy \(D=\dfrac{39}{200}\)
câu 5 :5 nhân 25 nhân 125 nhan 625 nhan 5 mu 7
cau 6 : 2 nhan 4 nhan 8 nhan 16 nhan 256
4 nhan 5 nhan 6 / 8 nhan 10 nhan 12
4 x 5 x 6/8 x 10 x 12
= 4 x 5 x 3/4 x 10 x 12
3 x 5 x 10 x 12
= 1800
1 phan 5 nhan 8 cong 1 phan 8 nhan 11 cong 1 phan 11 nhan 14 +..........+1 phan x nhan (x+3)=101 phan 1540
1 phan 5 nhan 8 cong 1 phan 8 nhan 11 cong 1 phan 11 nhan 14 +..........+1 phan x nhan (x+3)=101 phan 1540
\(\frac{1}{5.8}+\frac{1}{8.11}+...+\frac{1}{x.\left(x+3\right)}=\frac{101}{1540}\)
\(\frac{3}{5.8}+\frac{3}{8.11}+...+\frac{3}{x.\left(x+3\right)}=\frac{303}{1540}\)
\(\frac{1}{5}-\frac{1}{8}+\frac{1}{8}-\frac{1}{11}+...+\frac{1}{x}-\frac{1}{x+3}=\frac{303}{1540}\)
\(\frac{1}{5}-\frac{1}{x+3}=\frac{303}{1540}\)
\(\frac{1}{x+3}=\frac{1}{308}\)
\(\Rightarrow x+3=308\)
\(x=305\)
1 phan 5 nhan 8 cong 1 phan 8 nhan 11 cong 1 phan 11 nhan 14 +..........+1 phan x nhan (x+30+101 phan 1540
\(\frac{1}{5.8}+\frac{1}{8.11}+\frac{1}{11.14}+...+\frac{1}{x.\left(x+30+\frac{101}{1540}\right)}\)
Phải gì không .
ghi nham la the nay
1 phan 5 nhan 8 cong 1 phan 8 nhan 11 cong 1 phan 11 nhan 14 +..........+1 phan x nhan (x+3)=101 phan 1540
[X nhan 7 cong 8 ] chia 5 = 10
280 chia [7 cong 3 nhan X] = 4
[ X nhan 5] nhan 19 chia 13= 57
6 nhan [28 - 8] nhan X ] = 72
4 nhan [ 36 - 4 nhan X] = 3,2
[X - 15] nhan 3 chia 12 =6
[ X chia 4 cong 6] nhan 7=70
[ X chia 2 cong 50] chia 5=12
5 nhan [ 7 cong 3 nhan X] = 140
help me ////\\\\\
tim X nha mn jup mk ik mk dg voi lam
a) (x.7 +8):5=10
x.7 +8= 10.5=50
x.7= 50-8=42
x= 42:7=6
b) 280: (7+3.x)=4
7+3.x= 4.280= 1120
3.x= 1120-7 =1113
x= 1113: 3= 371
c) (x.5) .19:13= 57
(x.5). 19= 57.13= 741
x.5= 741: 19= 39
x= 39:5 =7,8
d) 6.(28-8).x = 72
20.x= 72:6= 12
x= 12: 20= 0,6
e) 4. (36-4.x)= 3,2
36-4.x= 32:4= 0,8
-4.x= 0,8- 36= -35,2
x= -35,2 : -4 = 8,8
f) (x-15).3 :12= 6
(x-15).3 = 6. 12= 72
x-15= 72: 3= 24
x= 24+ 15= 39
g) (x:4+ 6) . 7 = 70
x:4+6= 70:7= 10
x:4= 10-6= 4
x= 4.4 = 16
h) (x:2+50) :5= 12
x:2+ 50= 12.5= 60
x:2= 60-50= 10
x= 10.2=20
l) 5.(7+3.x)= 140
7+3.x= 140:5 = 28
3.x= 28-7 =21
x= 21: 3= 7
k cho mình nhe
1 a, 3 va 1/5 - 2 va 1/6 + 1/5
b, 5 va 12/13 - 2 va 15/26 + 1/26
c, 7 va 1/12 + 1/12 - 6 va 1/4
2 tinh gia tri bieu thuc
a, 3 va 2/9 - [1 va 5/8 + 1 va 2/9 ] - 3/8
b, 4 va 2/5 - 1 va 3/7 - 1 va 4/7 + 1/5
c, 1 va 9/12 - 5/4 - 1/2
3 tinh
a, 6 nhan 7 nhan 8 nhan 9 nhan 1 tren 18 nhan 16 nhan 14 nhan 12 nhan 2
b, 4 nhan 15 nhan 9 nhan 24 tren 3 nhan 12 nhan 8 nhan 5
4 rut gon cac phan so
a, 96/150 ; 255/408 ; 630/224
b, 1515/1717; 352352/470470; 200620062006/200520052005
5 so sanh cac phan so
a, 7/9 va 9/7 ; b, 135/120 va 13/8; c, 3535/4848 va 5/8 ; d, 650650/480480 va 222222/144144
6, so sanh hai phan so
a, 2005/2006 va 2006/2007 ; b, 2008/2007 va 2007/2006
cac ban lam tung buoc nha
bai 3 : tim x
6 nhan ( x+9845 ) = 29042 nhan 6
(x chia 3) nhan 8 = 8 nhan 3198
bai 7 : tim x
191+ x + 9 = 43 nhan 5
x nhan 25 nhan 4 = 125 nhan 8
bai 8 : tim x
128 nhan x - 12 nhan x - 16 nhan x = 5208000
x nhan 27 + x nhan 30 + x nhan 43 =210500
Lời giải đầy đủ:
Bài 3:tìm x
A,
6.(x+9845)=29042.6
(x+9845)=29042.6:6
x+9845=29042
x=29042-9845
x=19197.
B,
(x:3).8=8.3198
(x:3)=3198.8:8
x:3=3198
x=3198.3
x=9594.
Bài 7:
A/191+x+9=43.5
200+x=215
x=215-200
x=15.
B/x.25.4=125.8
x.100=1000
x=1000:100
x=10.
Bài 8:
A/ 128.x-12.x-16.x=5208000
(128-12-16).x=5208000
100.x=5208000
x=5208000:100
x=52080.
B/ x.27+x.30+x.43=210500
x.(27+30+43)=210500
x.100=210500
x=210500:100
x=2105.
K mình nhé!