5(3a方-ab方)-(ab方+3a方b)
=15a方-5ab方-ab方-3a方b
=15a方-6ab方-3a方b
=15*1/4-6*1/2*1/9-3*1/4*1/3
=15/4-1/3-1/4
=14/4-1/3
=7/2-1/3
=21/6-2/6
=19/6
5(3a方-ab方)-(ab方+3a方b)
=15a方-5ab方-ab方-3a方b
=15a方-6ab方-3a方b
=15*1/4-6*1/2*1/9-3*1/4*1/3
=15/4-1/3-1/4
=14/4-1/3
=7/2-1/3
=21/6-2/6
=19/6