a) x+(x+1)(x+2)+....+(x+2010)=2029099
( x + x + x + ... + x ) + ( 1 + 2 + .... + 2010 ) = 2029099
2011x + 2021055 = 2029099
2011x = 2029099 - 2021055
2011x = 8044
x = 8044 : 2011
x = 4
vậy x = 4
x + ( x + 1 ) + ( x + 2 ) + .... + ( x + 2010 ) = 2029099
x . 2011 + ( 1 + 2 + ... + 2010 ) = 2029099
x . 2011 + 2021055 = 2029099
x . 2011 = 2029099 - 2021055
x . 2011 = 8044
x = 8044 : 2011
x = 4
Xx(1+2+3+4.....+2010)=2029099
Có 2010 so
(2010+1)x2010:2=2021055
Co 2011 so X
2021255:2011==1005
X=1005