Step-by-step explanation:

FOIL METHOD po gamitin nyo madali lang

>First (3x)•(2x)=6x²

>Outside (3x)•7=21x

>Inside -4•(2x)=-8x

>Last -4•7=-28

simplify outside and inside becomes

21x-8x= 13x

Therefore,

6x²+13x-28