( x + 1 ) + ( x + 2 ) + ( x + 3 ) + ... + ( x + 210 ) + ( x + 211 ) = 23632
x + 1 + x + 2 + x +3 + .... + x + 210 + x + 211 = 23632
( x + x + x + .... + x ) + ( 1 + 2 + 3 + ... + 210 + 211 ) = 23632
211x + 22366 = 23632
211x = 23632 - 22366
211x = 1266
=> x = 1266 : 211 = 6
Vậy x = 6
ta có (x+1) + (x+2) + (x+3) + ... + (x+210) + (x+211) = 23632
= X + ( 1 + 2 +3 + 4 + .... + 210 + 211 ) = 23632
= X + ( 1 + 211 ) + ( 2 + 210 ) + .... =23632
= X + 212 x 105 =23632
= X + 22260 = 23632
= X = 23632 - 22260
= X = 1372