26.4*25-26*250
=(26+0.4)*25-26*250
=26*25+0.4*25-26*250
=26*25*(1-10)+10
=-(20+6)*25*9+10
=-20*25*9-6*25*9+10
=-4500-1350+10
=-5840
26.4*25-26*250
=(26+0.4)*25-26*250
=26*25+0.4*25-26*250
=26*25*(1-10)+10
=-(20+6)*25*9+10
=-20*25*9-6*25*9+10
=-4500-1350+10
=-5840