2x10^3+7x10^2+8x10+7
2x10=...
3x10=...
4x10=...
5x10=...
6x10=...
7x10=...
8x10=...
9x10=...
10x10=...
Nhớ viết cả phép tính nhé!Thanks
2 x 10 = 20
3 x 10 = 30
4 x 10 = 40
5 x 10 = 50
6 x 10 = 60
7 x 10 = 70
8 x 10 = 80
9 x 10 = 90
10 x 10 = 100
2x10= 20
3x10= 30
4x10= 40
5x10= 50
6x10= 60
7x10= 70
8x10= 80
9x10= 90
10x10= 100
a=[(7^2x10^3+6^2x10^3+2x10^4-5000):5^3]:8
a = (7^2.2^3+6^2.2^3+2.5.2^4-40) : 8
= (7^2.8+6^2.8+2^2.5.8-5.8) : 8
= 7^2+6^2+2^2.5-5 = 49+36+20-5 = 100
k mk nha
Tính nhanh : 2/5x7 3/7x10 4/10x14 7/14x21 9/21x30
\(A=\frac{3}{1^2x2^2}+\frac{5}{2^2x3^2}+\frac{7}{3^2x4^2}+............+\frac{19}{9^2x10^2}\)
d) 4x[(3+3^7:3^4):10+97]-300
e) 5x[(92+2^5:2):5^2+24]-7^2
f)3^2x[(5^2-3):11]-2^4+2x10^3-(1^48)^49
tinh nhanh
B = 2/5x7 + 3/7x10 + 4/10x14 + 7/14x21 + 9/21x30
B = ?
B = 2/5x7 + 3/7x10 + 4/10x14 + 7/14x21 + 9/21x30
B = 1/5 - 1/7 + 1/7 - 1/10 + 1/10 - 1/14 + 1/14 - 1/21 + 1/21 - 1/30
B = 1/5 - 1/30
B = 6/30 - 1/30
B = 5/30 = 1/6
tinh nhanh
B = 2/5x7 + 3/7x10 + 4/10x14 + 7/14x21 + 9/21x30
B = ?
B = 2/5x7 + 3/7x10 + 4/10x14 + 7/14x21 + 9/21x30
B = 1/5 - 1/7 + 1/7 - 1/10 + 1/10 - 1/14 + 1/14 - 1/21 + 1/21 - 1/30
B = 1/5 - 1/30
B = 6/30 - 1/30
B = 5/30 = 1/6
soyeon làm sai vì nó là 2/5x7 chứ có phải là 1/5x7 đâu mà lại tách ra như thế?
3/4x6+3/6x8+3/8x10+.............+3/nx(n+2)=9/25
tìm y:
(2/2x4 + 2/4x6 + 2/6x8 + 2/8x10) x y = 1/3
`(2/(2xx4)+2/(4xx6)+2/(6xx8)+2/(8xx10))xxy=1/3`
`=>(1/2-1/4+1/4-1/6+1/6-1/8+1/8-1/10)xxy=1/3`
`=>(1/2-1/10)xxy=1/3`
`=>(5/10-1/10)xxy=1/3`
`=>4/10xxy=1/3`
`=>2/5xxy=1/3`
`=>y=1/3:2/5`
`=>y=1/3xx5/2`
`=>y=5/6`