(2а+3х)(5а-х)-(а+х)(10а-3х)= 10a²-2xa+15xa-3x²-(10a²-3xa+10xa-3x²)=10a²-2xa+15xa-3x²-10a²+3xa-10xa+3x²=16xa
(2а+3х)(5а-х)-(а+х)(10а-3х)= 10a²-2xa+15xa-3x²-(10a²-3xa+10xa-3x²)=10a²-2xa+15xa-3x²-10a²+3xa-10xa+3x²=16xa