2a) (x-9)(x7+x6+x5+x4+x3+x2+x+1)
x8+x7+x6+x5+x4+x3+x2+x+1-9x7-9x6-9x5-9x4-9x3-9x2-9x-9
x8-8x7-8x6-8x5-8x4-8x3-8x2-8x-8
2b) (10)8-8(10)7-8(10)6-8(10)5-8(10)4-8(10)3-8(10)2-8(10)-8
100,000,000-80,000,000-8,000,000-800,000-80,000-8,000-800-80-8
11,111,112
2c) (10-9)(107+106+105+104+103+102+10+1)
(1)(11,111,111)
11,111,111
2d) Jeremy was incorrect; 11,111,112≠11,111,111