4ab *(7a+6b)+2a*(ad -8b²)
4ab*(7a+6b)+2a*(ab-8^2)=28a^2b+24ab^2+2a^2b-16ab2=26a^2b+8ab^2
4ab *(7a+6b)+2a*(ad -8b²)=4ab*7A+4AB*6B+2A*AB-2A*8BB=28AAB+24ABB+2AAB-16ABB=30AAB+8ABB=2AB(15AA+4BB)