Các câu hỏi tương tự
Tinh tong: a) 9 + 99 + 999 + ... + 999...999 ( co 10 c/s 9 )
b) Tim x, biet: 1/21 + 1/28 = 1/36 +... + 2/x(x+1) = 2 / 9
tim x, biet:
a,(3x-15)^7=0
b,4^2x-6=1
c,(3-x)^20:(3-x)^10=1(x khac 3)
d,(x-6)^3=(x-6)^2
tim stn x biet 1/3 + 1/6 + 1/10 +...+2/x x (x - 1) = 2005/2006
tim x biet :1/3+1/6+1/10=..+2/x.(x+1)=2001/2003
a)(1/2+1)x(1/3+1)x(1/4+1)x...x(1/999+1)
b)(1/2-1)x(1/3-1)x(1/4-1)x...x(1/1000-1)
c)3/22 x 8/32 x 15/42 x .... x 99/102
help me please
tim x thuoc N biet 1/3+1/6+1/10...+1/x.(x+1) :2=2001/2003
Tim x biet: 1/10+1/15+1/21+.........+2/x.(x+1) = 2010/2012
tim x biet :
a) 1/3 + 1/6 +1/10+ ...+ 2/ x*(x+1)
b) 1/2 + 1/6 +1/12 + ...+1/x=72/73
Tim x thuoc so nguyen,biet:
a. (x+1).(x-2)=0
b.10+3(x-1)=10+6x
c. x-96=(9443-x)-15