Tìm x biết :
\(\frac{1}{5\times8}+\frac{1}{8\times11}+\frac{1}{11\times14}+.....+\frac{1}{x\times\left(x+3\right)}=\frac{101}{1540}\)
Bai 1 :Tinh nhanh
A= 3 / 5 x 8 + 3 / 8 x 11 + 3 / 11 x 14 + ....... + 3 / 95 x 98 + 3 / 98 x 101
Bai 2 :So sanh phan so voi 1:
2009 x 2011 + 2010 / 2008 x 2012 + 2009
Tìm x:
a. ( x + 2 ) + ( x + 5 ) + ( x + 8 ) + ( x + 11 ) + ( x + 14 ) = 75
b. ( x + 1 ) + ( x + 3 ) + ( x + 5 ) + ... + ( x + 101 ) = 5400
3 x ( 1/7 + 1/3 - 3/14 ) : 11/14
( 8/5 + 11/5 ) x 11/10 + ( 17/10 - 4/5) : 3/7
tính bằng cách hợp lí nhất
1/1*2+1/2*3+1/3*4+......+1/99*100+1/100*101
3/5*8+3/8*11+3/11*14+.........3/605*608+3/608*611
Tìm x
a) 1/2 : 3 + x = 14/5
b) 8/5 : x : 7/4 = 11/6
c) 24/10 + x : 3/4 = 11/3
1 / 8 x 11 +1 / 11 x 14 + 1 /14 x 17 + ... + 1 / 602 x 605 + 1 / 605 x 608
1 / 8 x 11 +1 / 11 x 14 + 1 /14 x 17 + ... + 1 / 602 x 605 + 1 / 605 x 608
1 / 8 x 11 +1 / 11 x 14 + 1 /14 x 17 + ... + 1 / 602 x 605 + 1 / 605 x 608